Pirates have kidnapped seven Russians and one Ukrainian after attacking the cargo ship the BBC Caribbean off the coast of Nigeria, the Russian embassy said on its official Twitter account.
The embassy has asked Nigerian authorities to assist in locating the abducted people, it said late on Tuesday.
The Nigerian navy and police were not immediately available for comment.
The general cargo vessel BBC Caribbean is managed by Briese Schiffahrts.
"The armed pirates approached (the vessel) in a boat, captured the crew and left on the boat at the direction of the Nigerian shores," said Pavel Fedulov, the director of a Briese Schiffahrts subsidiary in St Petersburg, according to Russian news organisation RBC.
No firearms were used during the attack, he was quoted as saying.
Security experts class West Africa's waters, especially off Nigeria where most of the pirates originate, as some of the world's most dangerous, with attackers often targeting oil tankers as well as hostages to ransom.
As oil prices have dropped, pirate gangs have taken to abducting crew for ransom as a way to make more money.
Security analysts say the pirates have emerged from militant groups in Nigeria's oil-producing Niger Delta.
The Nigerian navy on Wednesday rescued an oil tanker, the MT Gaz Providence, and its 21 crew members from a separate pirate attack near Bonny Island, the navy said in a statement.
Another attack was also fended off by the navy south of Akassa in Delta state, where pirates twice tried to hijack the oil tanker MT Rio Spirit, the navy said.
The statement did not address the kidnapping of the crew members of BBC Caribbean.
(Reporting by Angela Ukomadu; Additional reporting by Tife Owalabi, Ulf Laessing and Vladimir Soldatkin; Writing by Paul Carsten; Editing by Alison Williams)