MOSCOW, August 21 (RIA Novosti) - Russia's probe into the hijacking of the Arctic Sea cargo vessel is likely to involve the law enforcement agencies of other countries, Russia's Prosecutor General's Office said on Friday.

The Maltese-flagged vessel, which had been missing in the Atlantic for more than two weeks, was found off Cape Verde on Monday with 15 Russian crewmembers and eight suspected hijackers on board. The vessel was freed by the Russian Ladny missile frigate without a single shot being fired.

Four Estonians, two Latvians and two Russians were arrested on board the vessel on suspicion of hijacking and are currently in Russia being questioned.

Latvia's Foreign Ministry confirmed on Friday that it had received information from official Russian channels that two of the suspected hijackers were from Latvia, but has not released the names of the detainees.

There has been no formal response from Estonia's Foreign Ministry.

The suspected hijackers could face up to 20 years in prison.

Some members of the crew and all eight of the alleged hijackers arrived in Moscow on Thursday on separate Il-76 Candid military planes.

Russian Defense Minister Anatoly Serdyukov said on Thursday that four crewmembers, including the captain, remained on duty on board the Arctic Sea, which is being towed to Russia's Black Sea port of Novorossiisk for further investigation.