A total of 139 graves were found at 28 abandoned squalid detention camps believed to have been used by human traffickers to hold people fleeing Myanmar and Bangladesh.
"These graves are believed to be a part of human trafficking activities involving migrants," Malaysia's Home Minister Zahid Hamidi told reporters in Kuala Lumpur.
It is not clear how many corpses – which carry sings of torture - were recovered from the graves, but most of them carry several sets of skeletal remains.
"They have been there for quite some time. I suspect the camps had been operating for at least five years," Hamidi said.
Khalid Abu Bakar, a senior police official, said the exhumation work had started. However, he couldn't confirm yet whether the victims were Rohingyas or Bangladeshis.
'No longer a commodity'
The finding comes after 26 bodies were exhumed from trafficking camps in neighboring Thailand a week ago.
The refugee crisis has flared over the past few weeks following a crackdown on human traffickers by Thai authorities. As a result of the crackdown, an estimated 5,000 to 6,000 people were held in ships for days in international waters, as people smugglers in command of the vessels refused to bring people ashore.
Earlier this month, several abandoned boats carrying more than 1,000 people washed to shore on the Malaysian island of Langkawi, near Thailand. In reaction to increasing international pressure, Malaysia and Indonesia said on Wednesday, May 20, they would no longer be pushing back migrant vessels seeking to reach their shores, adding that both nations would let up to 7,000 Rohingya and Bangladeshi migrants stranded at sea come ashore and temporarily stay in their territory.
Jeffrey Labovitz, Chief of Mission at the International Organization for Migration (IOM) in Thailand, says the mass gravesfound in Malaysia have a direct link to the crackdown against human traffickers.
"Smuggler camps move and many operate at the same time. However, during different phases of crackdowns, camps move across the border or to islands. Each time they move there are delays and vulnerability grows. Ostensibly, the camps are transit centers where final payments are made for the last part of the journey," Labovitz told DW.
Experts say that if the family of the refugee does not pay the money demanded by smugglers, they are forced to stay longer in the camps, and are also tortured. They are not given anything to eat and are made immobile.
"They are forced to call home and plead for money. Those who do not come up with money develop beriberi over time," the IOM chief said, adding that beriberi was "a textbook disease in that most doctors have never seen cases. It is not something of the civilized world."
Beriberi victims resemble human skeletons; they can no longer support their weight and walk. "It is the last stage before death," underlined Labovitz.
"Those with beriberi are no longer a commodity to the smuggler. They can neither walk nor work. They become the ultimate example that no one will be let go without paying."
Stateless and persecuted
The crisis has once again highlighted the largely-ignored plight of the Rohingyas. Most of the refugees coming towards Thailand, Malaysia and Indonesia are either Rohingyas from Myanmar or Bangladesh.
Myanmar's Rohingyas live predominantly in the western state of Rakhine. They are not officially recognized by the government as an ethnic minority group, and for decades they have been subjected to discrimination and violence by the Buddhist majority.
Viewed by the United Nations and the US as one of the world's most persecuted minorities, thousands of Rohingya from Myanmar and Bangladesh flee their countries every year in a desperate attempt to reach Malaysia and Indonesia.
The UN refugee agency estimated that 25,000 Rohingya and Bangladeshi migrants boarded smugglers' boats in the first three months of 2015, double the amount for the same time period in 2014.
Most of them are not citizens and outbreaks of sectarian violence have prompted many to flee. "An entire population feels their only option is to seek asylum by sea," Matthew Smith of Fortify Rights told DW.
In the meantime, Thailand has called for a regional summit on May 29 to address the underlying causes of the crisis such as the smuggling networks, how they work across countries and how they can be stopped. Myanmar has also indicated it would be taking part in the meeting.