Moscow was increasingly concerned about the fatalities among Libya's civilian population, including the death of three grandsons and the youngest son of Muammar Gaddafi, the Russian Foreign Ministry said in a statement on Sunday.

Russia thus doubts the statement by the NATO coalition which says NATO's air strike are not targeting Libyan leader Gaddafi, the statement said.

"Moscow perceives with growing alarm the reports about victims among civilians. The statements by the coalition members that the airstrikes against Libya are not aimed at physically destroying Muammar Gaddafi and his family members cause serious doubts," it reads.

The Foreign Ministry said the "disproportionate use of force" in Libya has led to devastating consequences and death of innocent people.

Therefore, the ministry once again called for "strict adherence to the provisions of the international resolutions regarding the Libyan conflict, an immediate cease-fire and the start of a political settlement process without any preconditions."

Earlier Sunday, Konstantin Kosachyov, head of the State Duma's international committee, said in an interview with local media that the NATO operation in Libya which killed Gaddafi's son and grandsons has gone beyond the framework of the UN Security Council mandate and it was in fact a major interference in Libya's internal affairs.

"More and more facts indicate that the purpose of the coalition is the physical destruction of Gaddafi," the Russian parliamentarian was quoted by RIA Novosti news agency as saying.

A NATO airstrike on a house where the Libyan leader and his family were staying at the time killed Saif al-Arab Gaddafi, 29, the youngest son of Gaddafi, and three of Gaddafi's grandchildren, a government spokesman said Sunday.