Russian Human Rights Commissioner Tatyana Moskalkova has asked her Ukrainian counterpart Liudmyla Denisova to look into the circumstances of the detention of a Russian tanker at a Ukrainian port and find out the composition of its crew.

"Moskalkova has had a phone call with Denisova concerning media reports on the detention of a Russian tanker at the Izmail Port," the Russian ombudsman's press service said on Thursday.

"Tatyana Moskalkova has asked Liudmyla Denisova to look into the circumstances of the vessel's detention and find out the crew's composition; namely, whether there are citizens of the Russian Federation on board and how many, whether the sailors are receiving consular support, whether their rights have been violated, whether they have received essential food products and drinking water, and whether any crewmembers need medical attention," Moskalkova's press service said on Thursday.

Denisova, in turn, told Moskalkova she would clarify the situation surrounding the tanker's crew with the Ukrainian Security Service, and the two agreed to continue a humanitarian dialogue, it said.