"The information we possess shows there is no environmental damage, no oil spill", the agency said.
Meanwhile, rescue teams are searching for sailors who went missing after a fire erupted on board two Tanzania-flagged tankers in the Kerch Strait, the Russian Federal Agency of Maritime and River Transportation (Rosmorrechflot) said.
"As of 6 a.m. local time [on Tuesday, 03:00 GMT] the [rescue teams] ended the rescue operation and started the search operation due to the lack of hope of finding the survivors", the agency's spokesperson told reporters.
According to preliminary information, the fire broke out on 21 January during the transfer of liquefied natural gas from one vessel to another.
Rosmorrechflot reported that 12 people were rescued, 10 died, and 10 were reported missing.