The fire has now been extinguished, Russian emergency services told Interfax agency. Even though traffic has resumed in a limited manner, trains are delayed, with the ferry service expected to begin operations later Saturday.
The blast "set fire to seven oil tankers being carried by rail to Crimea," Russian news agencies cited the national anti-terrorism committee as saying. Russia has launched a criminal probe into the event.
The road running along that part of the bridge was also badly damaged, according to the reports.
The 19-kilometer bridge (12-mile) holds symbolic importance for Russian President Vladimir Putin because it is a tangible symbol of Moscow's claims on the Crimean peninsula. It is also one of the main supply routes for Moscow to move military equipment into southern Ukraine.
Later on Saturday, Russian President Vladimir Putin signed a decree calling for tightened security for the Kerch Bridge and for energy infrastructure between Crimea and Russia. The presidential order put Russia's federal security service, the FSB, in charge of the effort, according to a Kremlin statement.
Here's more news on the war or concerning the war from October 8:
Crimean bridge blast a 'terrorist attack' — Russian lawmaker
Russian lawmaker and foreign policy expert Leonid Sluzki called the blast that damaged part of the Kerch Bridge a "terrorist attack."
Sluzki said that "consequences will be inevitable" if it is proven that the attack was carried out by Ukraine. He added that Russia had experience fighting terrorists and that attacks on the bridge had to be prevented.
"This can be an act of state terrorism for which, as we see, there is applause in European capitals," Sluzki said.
Sluzki heads the Foreign Affairs Committee in Russia's parliament. He is the leader of the right-wing nationalist Liberal Democratic Party, founded by Vladimir Zhirinovsky, who died earlier this year.
Crimean bridge reopens to passenger trains, Moscow-installed official says
The Kerch Bridge has partially reopened to rail traffic, Moscow-backed Crimean leader Sergei Aksyonov said.
Aksyonov said in a post on Telegram that the bridge remained closed to trucks for the time being.
Russian rail operator Grand Service Express said that the first two trains out of Crimean cities Simferopol and Sevastopol departed for Moscow and St Petersburg at 17:10 and 17:15 local time (1410 and 1415 GMT).
Earlier, Russia's Transport Ministry said that two undamaged lanes continue to be used.
NATO should do more against Putin's 'delusions' of grandeur, says German defense minister
German Defense Minister Christine Lambrecht said NATO should do more to protect itself against Russia. She was visiting German troops in Lithuania when she made the comments Saturday.
Lambrecht said the current situation meant that member states had to do more together and that there was no way to know "how far Putin's delusions of grandeur can go."
She added that Russia's war of aggression in Ukraine was getting more "unscrupulous" and Russia's threat of nuclear weapons showed that Russian authorities have no "scruples."
Russia says limited traffic has resumed on Crimean bridge
Russia's Transport Ministry said traffic for cars and buses had resumed on intact lanes of the Crimean bridge following the explosion early Saturday morning.
Traffic would be restricted to crossing between Crimea and the Russian Taman peninsula in opposite directions.
Sergey Aksyonov, the head of the Russian occupation government in Crimea, said on social media that heavy goods would have to wait to cross by ferry.
The extent of damage from the explosion is not fully clear yet.
Russia names new top commander for Ukraine
Russia's Defense Ministry has named General Sergei Surovikin as the new top commander for all Russian forces in Ukraine, it said in a statement Saturday.
Surovikin, 55, was born in Siberia's Novosibirsk and has combat experience in the 1990s conflicts in Tajikistan and Chechnya. He was also the commander of Russian forces in Syria from April 2019 until September 2019.
Russia reportedly sacked the commanders of two of Russia's five military regions earlier this week as well.
Zaporizhzhia nuclear plant switches to diesel generators as shelling cuts power line
Overnight shelling has cut the power line supplying the Russian-occupied Zaporizhzhia nuclear power plant, forcing it to switch to emergency diesel generators, the International Atomic Energy Agency said on Saturday.
Zaporizhzhia, Europe's largest nuclear plant, was seized by Russian forces in March but continues to be run by Ukrainian staff. The last operating reactor of the plant was closed earlier this September.
The International Atomic Energy Agency (IAEA) said Sunday that hitting the plant's sole source of external power was "tremendously irresponsible."
Rafael Grossi, the head of IAEA, said that the nuclear plant "must be protected" and has called for a demilitarized zone around the facility.
Even though Zaporizhzhia's six reactors are shut down, the nuclear fuel in them still needs cooling to prevent a nuclear meltdown. That requires a constant supply of electricity.
Criticism aimed at Russian high command increasing, says UK intelligence
The UK's Defense Ministry said increasingly diverse actors within Russia have joined voices in criticism of the Russian military high command following continued setbacks for Moscow over the last two weeks.
Critics have included Chechen leader Ramzan Kadyrov and Wagner group private military company owner Yevgeny Prigozhin, state-approved TV presenters and pop stars, according to the UK intelligence update.
Kadyrov and Prigozhin are likely being perceived as informal figureheads of the "pro-war" bloc whose criticism hinges on arguments for greater state commitment and willingness to escalate, according to the intelligence update.
Ukrainian reaction shows its 'terrorist' nature, says Russia
Maria Zakharova, the spokesperson for Russia's Foreign Ministry, slammed Kyiv's response to Kerch bridge incident.
"The reaction of the Kyiv regime to the destruction of civilian infrastructure shows its terrorist nature," Zakharova said on Telegram.
The fire prompted gleeful messages from some Ukrainian officials, but no direct claim of responsibility.
Crimea holds symbolic value for Russia and is key to sustaining military operations in the south of Ukraine.
Mykhailo Podolyak, an adviser to Ukrainian President Volodymyr Zelenskyy, said on Twitter that: "Crimea, the bridge, the beginning."
"Everything illegal must be destroyed, everything stolen must be returned to Ukraine, everything occupied by Russia must be expelled," Podolyak added.
Top Crimea lawmaker blames 'Ukrainian vandals'
Crimean parliament head Vladimir Konstantinov said the bridge was damaged by "Ukrainian vandals."
"They now have something to be proud of: for 23 years of their economic management they did not manage to build anything worthy of attention in Crimea, but they managed to damage the floor of the Russian bridge," he added on his Telegram channel.
Russian President Vladimir Putin ordered the creation of a committee to investigate the causes of the explosion. The committee said it had sent detectives to the scene.
Dramatic videos on social media showed the giant bridge on fire and partially collapsed into the sea.
The Kerch bridge is 19 kilometers long (11.8 miles) and was built by Russia after it declared Crimea to be Russian territory in 2014 in an illegal move condemned by much of the international community.
IMF approves funds of $1.3 billion for Ukraine
The International Monetary Fund (IMF) on Friday approved additional emergency funding of $1.3 billion (€1.33 billion), to support the Ukrainian economy.
The funding comes from a new emergency lending program and will help Ukraine curb financial losses, including the loss of grain export revenues.
"The scale and intensity of Russia's war against Ukraine that started more than seven months ago have caused tremendous human suffering and economic pain," the IMF said. The organization also praised Ukraine's government for maintaining financial stability during a challenging period.
The IMF said the Ukrainian economy is forecast to contract by 35% in 2022.
Explosions rock Kharkiv
Explosions were reported in the northeastern Ukrainian city of Kharkiv in the early hours of Saturday sending plumes of smoke into the sky. A secondary round of explosions was heard after the first blasts.
It was not immediately known what caused the blasts. However, Kharkiv Mayor Ihor Terekhov wrote on Telegram that missile strikes had hit a medical facility and a commercial building.
Russia-backed forces claim new victories in Donetsk
Russian-backed proxy forces said they had captured territory in Donetsk in the east of Ukraine.
Separatist forces said they had captured several villages near Bakhmut, an industrial town that has been subjected to weeks of Russian shelling.
AFP journalists in Bakhmut reported hearing heavy artillery and rocket launch systems.
The claims of new gains come as the Russian military, along with fighters from self-declared "republics" in eastern Ukraine, have been confronted with a Ukrainian counteroffensive that has pushed Russian forces out of territory in the east and south.
Late Friday, Ukrainian President Volodymyr Zelenskyy said that Ukrainian forces "this week alone" liberated 776 square kilometers of territory in Ukraine's east and 29 settlements, including six in the Luhansk region.
Mass burial site found near Lyman, Ukraine says
Ukrainian authorities said Friday that a mass grave has been uncovered near the eastern town of Lyman following the withdrawal of Russian troops.
Donetsk regional governor Pavlo Kyrylenko announced the discovery in a post on his Telegram channel along with images of crosses and crews in protective white suits digging through mounds of soil.
Kyrylenko said the victims could be both soldiers and civilians, and that exhumations were ongoing, as is an investigation into the number of victims.
Separate from the mass grave, Kyrylenko said 200 individual graves "where civilians are buried" were also uncovered in the area.
Lyman, a strategically important town located in the eastern Donetsk region, was liberated Saturday from Russian occupation.
Ukrainian officials have said Russian forces occupying Ukrainian territory have routinely committed rights abuses and atrocities.
Moscow denies the allegations despite mounting evidence of a Russian role in the torture and death of thousands of Ukrainians following occupation by Russian forces.
Before Kyrylenko's announcement Friday, Ukrainian First Deputy Minister of Internal Affairs Yevhen Yenin said that 530 bodies of civilians have been found in Ukraine's northeastern Kharkiv
region since September 7.
Most of the bodies were among the 436 exhumed from unmarked graves following the Russian withdrawal from the northeastern town of Izium.
Many of those bodies displayed injuries consistent with violent deaths, according to local officials.
Zelenskyy rules out 'preemptive' strikes on Russia
Ukrainian President Volodymyr Zelenskyy on Friday evening appeared to roll back statements he made Thursday calling for "preemptive strikes" to prevent Russia from using nuclear weapons.
The Kremlin quickly responded, accusing the Ukrainian president of fomenting calls for nuclear war.
In an interview with the BBC, Zelenskyy said the West "must use preventive kicks, not attacks," apparently referring to using sanctions as a deterrence.
Zelenskyy also warned Russia has begun to prepare its citizens for the potential use of a small tactical nuclear weapon.
"They begin to prepare their society. That's very dangerous," Zelenskyy said.
More DW content on the war in Ukraine
In an opinion piece, DW's Miodrag Soric says the 2022 Nobel Peace Prize winners focusing on civil rights in Russia is a "slap in the face" for Vladimir Putin.
In an exclusive interview with DW, Pakistani Foreign Minister Bilawal Bhutto rejected the need for Pakistan to take sides in the Ukraine conflict.
And DW also takes a look at who is supplying Russia with drones.
rm, ar/sms (Reuters, AP, dpa, AFP, Interfax)