A statement from Mikhail Kamynin, the official spokesman for the Foreign Ministry, said the Mujahideen Shura Council, a group linked to the al-Qaeda cell in Iraq that claimed responsibility for the abduction, had sentenced the diplomats to death.
The statement said the diplomats were "representatives of the Russian people, who have never waged a war against Islam anywhere...One of the Russian hostages is a Muslim."
Russian diplomat Vitaly Titov was killed during the attack on an embassy car in Baghdad. The kidnappers seized Fyodor Zaitsev, third secretary of the embassy, and also diplomats Rinat Agliulin, Anatoly Smirnov and Oleg Fedoseyev.
Foreign Minister Sergei Lavrov said earlier Wednesday that information about hostages had been coming in regularly.
"We do not intend to share this information with anyone, because the most important thing at the moment is to avoid undermining the efforts that are currently being undertaken to locate and release our citizens," he said.