Russian investigators opened two criminal cases to look into possible safety violations after at least one person was killed when the 136-metre Volgoneft 212 tanker, with 15 people on board, split in half with its bow sinking, footage published by state media showed, with waves washing over its deck.
The Russian-flagged vessel, built in 1969, was damaged and had run aground, officials said.
"There was a spill of petroleum products," Russia's water transport agency Rosmorrechflot said.
A second Russian-flagged ship, the 132-metre Volgoneft 239, was drifting after sustaining damage, the emergency ministry said.Â
It has a crew of 14 people and was built in 1973.
Both tankers have a loading capacity of about 4200 tonnes of oil products.
Official statements did not provide details on the extent of the spill or why one of the tankers sustained such serious damage.
President Vladimir Putin ordered the government to set up a working group to deal with the rescue operation and mitigate the effects of the fuel spill, news agencies cited Kremlin spokesman Dmitry Peskov as saying after Putin met with the ministers for emergencies and environment.
The vessels were in the Kerch Strait between mainland Russia and Crimea, which Russia annexed from Ukraine in 2014, when they issued distress signals.
Russia said more than 50 people and equipment, including Mi-8 helicopters and rescue tugboats, had been deployed to the area.
Svetlana Radionova, head of Russia's natural resources watchdog Rosprirodnadzor, said specialists were assessing the damage at the site of the incident.
Russia's Kommersant newspaper reported that the Volgoneft 212 tanker was carrying about 4300 tonnes of fuel oil.
Unverified video posted on Telegram showed some blackened water on stormy seas and a half-submerged tanker.
