A hijacked Russian oil tanker was freed by a Russian warship off the coast of Yemen on Thursday, and Somali pirates onboard the ship were seized, news agencies reported.

Russian Defense Ministry spokesman Alexei Kuznetsov confirmed that Russian anti-submarine vessel Marshal Shaposhnikov released the Russian tanker, Moscow University, with 23 crew members.

"Nobody was hurt among the tanker crew and the Russian military. The pirates have been detained and are being held onboard the Moscow University tanker," Kuznetsov said.

The rescue of the hijacked tanker and the safety of its crew members were also confirmed by Russian Foreign Ministry.

The special operation was conducted at around 3:00 a.m. Moscow time (2300 GMT Wednesday), said the RIA Novosti news agency.

The tanker, which was carrying 86,000 tons of crude oil to China, was captured off the Somali coast Wednesday morning.

A criminal case over the seizure of the vessel has been launched by Russian Prosecutor General's Office.