Russia on Monday called for the immediate release of four diplomats who were kidnapped in Baghdad earlier this month.
The statement by the Foreign Ministry was issued after an al-Qaida-linked group claimed it was holding the Russians, who were kidnapped June 3.
The Mujahedeen Shura Council, which claimed to have killed a fifth Russian during the seizure, also said it had abducted two American soldiers who were reported missing south of Baghdad.
Ministry spokesman Mikhail Kamynin said in a statement that Russia could not confirm the claims, but said officials were making strenuous efforts to secure the four diplomats' release.
"No matter what is behind this we again urge the kidnappers to release the Russian citizens immediately and ensure their safety," Kamynin said.
"The abduction of citizens of a country that is energetically helping to restore peace in Iraq" cannot be justified, he said, reports AP.
The Russian missile cruiser Varyag, which is currently staying in the waters of the Mediterranean Sea, blocked the US Navy aircraft carrier strike group in the Adriatic Sea