The leader for the USAID Disaster Assistance Response Team (DART), Stephen Allen, told reporters on Tuesday that each of the specialist teams will have 80 people each.
The teams will also have dogs and about 170,000 pounds of specialized tools and equipment, Allen said.
Thousands of children feared dead, says UN
UNICEF spokesperson James Elder said the earthquakes "may have killed thousands of children."
Syrian refugees in northwest Syria and Turkey were among the most vulnerable people affected, Elder said.
A UN humanitarian official in Syria said fuel shortages and the harsh weather were creating obstacles in their rescue mission. "The infrastructure is damaged, the roads that we used to use for humanitarian work are damaged," UN Resident Coordinator El-Mostafa Benlamlih told Reuters news agency from Damascus.
Mosques in Syria have opened their doors to families whose homes were damaged in Monday's quake.
UN provides $25 million in humanitarian assistance
The United Nations has released $25 million (€23 million) from its emergency fund in humanitarian assistance to the people affected by the earthquake in Turkey and Syria.
"As the people in the region deal with the devastating consequences of this tragedy, we want to tell them that they are not alone," Martin Griffiths, the UN emergency relief coordinator, wrote in a statement. "The humanitarian community will support them in every step of the way out of this crisis," he added.
Syria death toll rises to at least 1,832
At least 1,832 people have died in Syria after the 7.8-magnitude earthquake hit southern Turkey.
Syria's state news agency SANA said at least 812 people were killed and 1,449 people injured in the government-held provinces.
At least 1,020 people were killed in Syria's opposition-held northwest and 2,300 injured, with the toll expected to "rise dramatically," the White Helmets rescue team said.
The death toll in Turkey has risen to 4,544, officials say. The national Disaster and Emergency Management Authority says more than 26,000 people have been reported injured.
Syrian rescuers warn time is short after quake
The White Helmets rescue team operating in opposition-held territory in northwest Syria warned on Tuesday "time is running out" out to find survivors.
"Hundreds still trapped under the rubble. Every second could mean saving a life," the emergency organization said.
"We appeal to all humanitarian organizations and international bodies to provide material support and assistance to organizations responding to this disaster," it added.
At least 900 people were killed in the area and 2,300 injured with the toll expected to "rise dramatically."
Teams from nearly 30 countries around the world headed for Turkey or Syria.
But in the opposition-controlled parts of Syria work is hampered both by the civil conflict as Russian-backed government forces have virtually blockaded the area.
Sebastien Gay, the head of mission in Syria for Doctors Without Borders, said health facilities in the country's north were overwhelmed with medical personnel working around "around the clock to respond to the huge numbers of wounded.''
More than 8,000 people have been pulled from the debris in Turkey alone.
Glimmers of hope among the quake-torn ruins
Country is faced with a 'great disaster' — Erdogan
Turkish President Recep Tayyip Erdogan said the country is faced with "a great disaster," as a massive search and rescue effort gained momentum. A three-month state of emergency has been declared in 10 southeastern provinces in the country.
Erdogan said 53,317 search and rescue team members are working in the region, with more coming from across the country and around the world.
The Turkish president said $5.3 billion has been allocated for immediate use.
Erdogan said that people were being urged to stay away from the affected region in order keep the roads clear for emergency purposes.
Turkey's armed forces, including the navy and air force, were being deployed in active roles in search and rescue operations, while thousands of volunteers in coordination with the country's disaster management agency have been making their way to the region.
Erdogan also said thousands of construction vehicles and pieces of heavy equipment had been dispatched from across the country to help in affected areas.
Turkish and Kurdish communities in Germany have started to collect money, clothing and blankets for victims of the earthquakes in southern Turkey and northern Syria.
Volunteers began collecting aid in Berlin, Frankfurt and Munich shortly after the quakes struck on Monday.
"We didn't expect it to go this crazy, it's mad. We thought we would fill two vans and then send them off but it hasn't stopped since 10 this morning," organizer Levent Cukur told Reuters news agency.
Germany is home to large Turkish and Kurdish communities.
Germany pledges additional funds for quake victims
Germany's Foreign Minister Annalena Baerbock said an additional €1 million is being provided to the Malteser International aid organization.
Efforts are also underway to make more financial aid available to other aid organizations helping victims of the earthquake in Syria.
Speaking at a briefing in Berlin, Baerbock said Germany was also pushing for humanitarian access to Syria.
Germany calls on Russia to help with Syrian efforts
Syria's Red Crescent ready to deliver aid in all areas
The head of Syria's Red Crescent said the organization is ready to deliver relief aid to regions affected by Monday's earthquake — including opposition-held areas — and has called on the UN to help facilitate this.
"We do not differentiate between any of the Syrian people. We are the Syrian Arab Red Crescent for all the Syrian people," Khaled Hboubati said during a press briefing.
"We are ready to send an aid convoy through the cross line to the stricken areas in Idlib region (in northern Syria). If they (the opposition) opened a road for us, we will go. We have no problem with this," Hboubati said.
He appealed to the United Nations, which has coordinated the aid and relief operations in opposition-held areas, to assist.
Quakes leave thousands dead in Turkey, Syria
EU mobilizes 27 search and rescue teams
EU Crisis Commissioner Janez Lenarcic said 27 search and rescue teams from 19 European countries have been mobilized to search for survivors Turkey.
Lenarcic said medical teams were also being sent to help, together with 1150 rescuers and 70 rescue dogs.
"EU solidarity at its best," Lenarcic wrote on Twitter.
The deployment is being coordinated through the so-called EU Civil Protection Mechanism.
Countries in need can request emergency assistance from the EU and other countries participating in the scheme.
WHO chief concerned about silent areas of Turkey and Syria
The World Health Organization Director-General, Tedros Adhanom Ghebreyesus said there was concern about the areas of Turkey and Syria where information was yet come from.
"We're especially concerned about areas where we do not yet have information," Ghebreyesus told the WHO's executive board meeting in Geneva.
"Damage mapping is one way to understand where we need to focus our attention," the WHO chief said.
Turkey confirms 3,419 deaths in latest figures
Turkey's Vice President Fuat Oktay said that at least 3,419 people have been confirmed dead according to the latest disaster agency figures.
Oktay said that 20,534 had been injured, while search and rescue teams have managed to reach 8,000 people.
There have been 312 aftershocks recorded since the two devastating earthquakes which rocked southern Turkey and Northern Syria on Monday.
Oktay said that search and rescue operations were continuing despite adverse weather conditions, with heavy snow falling overnight, causing roads to be blocked.
More than 1,600 deaths reported in Syria
At least 1,602 people have been killed and thousands more injured according to state news and rescuers in Syria.
State news agency SANA reported that at least 812 people were killed in government-held areas.
The White Helmets rescue team operating in opposition held territory in the northwest reported there had been 790 people killed and 2,200 injured.
The death toll is expected to rise.
Large fire continues burning at Iskenderun port
A large fire has continued burning at the earthquake-stricken port of Iskenderun in southeast Turkey.
Footage from the scene showed black smoke billowing from burning containers at the port which is located on the Mediterranean Sea.
Its believed the fire was began when containers toppled over during Monday's earthquakes. According to state news Anadolu Agency, a vessel from the Turkish Coast Guard is trying to douse the flames.
5.4 magnitude earthquake recorded in eastern Turkey
The US Geological Survey has recorded a 5.4 magnitude earthquake in eastern Turkey, taking place at 08:11 UTC.
Turkey's Disaster and Emergency Management Authority (AFAD) meanwhile said there had been 243 aftershocks in the Turkey-Syrian border region since Monday's earthquakes.
AFAD chair Yunus Sezer provided the latest figures and said bad weather conditions were impacting search and rescue operations.
Rula Amin, UNHCR spokesperson for the Middle East and North Africa, told DPA news agency that people were too afraid to stay in their homes but had nowhere to go in freezing weather conditions.
Earthquake has directly affected 13.5 million people — Turkey environment minister
Turkey's Minister of Environment and Climate Change, Murat Kurum said that the earthquakes which struck southern Turkey had impacted 13.5 million people.
Kurum said search and rescue teams were working to reach people trapped beneath the rubble of collapsed buildings, and that the first 72 hours were critical.
Seven days of national mourning have been announced following the devastating earthquakes, considered to be one of the strongest recorded in a century.
Ten provinces in southern Turkey have been affected.
More than 3,300 deaths in Turkey alone — AFAD
Turkey's Disaster and Emergency Management Agency (AFAD) said that 3,381 people were now confirmed to have died following Monday's devastating earthquakes.
In a morning briefing the disaster agency also said 20,436 people have been injured, as search and rescue efforts continue for people trapped beneath the rubble and debris of destroyed buildings.
AFAD said that 5,775 buildings had collapsed, while 11,802 buildings had been damaged.
The disaster agency said there were over 24,000 personnel actively working in the disaster area, with various agencies and volunteers involved in rescue efforts.
It was also reported that there had been no letup in the adverse weather conditions, which was presenting a challenge to rescue teams operating in affected areas.
Death toll in Turkey and Syria rises to over 4,300
The death toll from the devastating earthquakes in the Turkish-Syrian border area has risen to more than 4,300.
An official with Turkey's disaster agency said at least 2,921 people were killed and 15,834 others injured in the south of the country.
And at least 1,400 people have died in Syria, according to the Health Ministry and rescue organization White Helmets.
Turkey dispatches hundreds of rescue teams, ambulances
Rescue workers in Turkey and Syria continued efforts to rescue survivors from the rubble amid cold temperatures early Tuesday.
Turkish Health Minister Fahrettin Koca said 813 ambulances were in impacted areas, with 227 UMKE teams in deployment. UMKE teams are catastrophe-relief workers coordinated by the health ministry.
South Korea to send rescue workers, medical aid to Turkey
South Korea's President Yoon Suk Yeol has issued an order to send rescue workers and emergency medical items to Turkey, Yoon's office said Tuesday.
"Yoon ordered related government agencies ... to come up with additional support measures in case needed by Turkey," the presidential office said in a statement.
Biden vows aid to Turkey in Erdogan phone call
US President Joe Biden spoke with Turkish President Recep Tayyip Erdogan late Monday, and pledged "any and all" assistance needed to help Turkey following the catastrophe.
Biden "reaffirmed the readiness of the United States to provide any and all needed assistance to our NATO ally Turkey in response to this tragedy," the White House said in a statement.
White House National Security Council spokesperson John Kirby also said the Biden administration was sending two, 79-person urban search and rescue teams to support Turkey's efforts.
Summary of Turkey-Syria earthquake events on Monday
A magnitude 7.8 quake rippled through Turkey and Syria early on Monday, toppling entire apartment blocks, wrecking hospitals, and leaving thousands more people injured or homeless. Another 7.5 tremor occurred later in the day.
World leaders and international organizations pledged support and humanitarian aid, as Turkey's President Recep Tayyip Erdogan has declared seven days of national mourning following the deadly quakes.
Turkey's government has declared a "level 4 alarm" that calls for international assistance. The country has also activated the EU civil protection mechanism.
The EU has dispatched almost 20 rescue teams coming from 17 European countries for Turkey. The bloc is looking into the possibility of mobilizing emergency medical teams, which is also part of Turkey's request for help.
The UN General Assembly observed a minute's silence in tribute to the victims. It also appealed to other countries to provide assistance to a region already scarred by conflict with only limited access for humanitarian aid.
Some historical buildings were destroyed as a result of the quake in the provinces of Aleppo, Hama, and Tartus, the Syrian Cultural Ministry said. The most notable damage reported was that which hit the historic Aleppo Citadel.