The alleged deaths of a group of Somali pirates who were set free after hijacking a Russian tanker near the Gulf of Aden have sparked heated debate in the Russian media.

Ten pirates were captured and one killed in an operation on May 6 to free the Moscow University tanker, captured on May 5.

A top-ranking source in Russia's Defense Ministry said on Tuesday the pirates had been disarmed and set adrift in a rubber boat without navigation equipment. The Russian military concluded that the hijackers perished as their boat disappeared from radars an hour after they were released.

Editor-in-chief of the Maritime Bulletin magazine Mikhail Voitenko told Russian daily Gazeta the pirates had obviously been "killed."

"When they [the military officials] realized there would be difficulties, they invented the story about the release. And now, to bring the story to a close, they added this information about the pirates perishing at sea," Gazeta quoted Voitentko as saying.

"If they did perish at sea, that would also be murder, just in a more sophisticated form," he said, adding that fighting pirates off the Somali coast has become a kind of "safari" for the military, "with zero danger and the chance of rewards and glory."

According to the Defense Ministry source, the Russian military officials were forced to release the pirates as there is no international legal base to carry out prosecution procedures against hijackers and the nationality of the detained pirates was not allowed to be revealed.

Russian daily Nezavisimay Gazeta said the story left many unanswered questions, especially surrounding the repercussions of the incident.

"It is known that so far pirates have been trying to leave captured sailors alive. Now, it cannot be ruled out that they will take harsher and, God forbid, crueler action, especially if there are Russians among the crew of captured vessels," the paper said.

It added that many Somali pirates will be aware of the fact that the Russians knew the pirates would perish after being sent adrift in a rubber boat without navigation equipment and other pirates are likely to try to avenge the deaths of their comrades.

Russian President Dmitry Medvedev pledged last week to punish pirates who take vessels hostage off the Somali coast "with the full force of maritime law."

Until a legal system allowing hijackers to be punished is created, "we will have to act as our forefathers did when they met pirates," he said.

MOSCOW, May 12 (RIA Novosti)