Russia's Foreign Minister Sergei Lavrov attends a luncheon hosted by U.N. Secretary-General Ban Ki-moon during the U.N. General Assembly in New York on Wednesday.
Russia's Foreign Ministry said Wednesday the legitimacy of U.S. air strikes against Islamic State are in doubt because of the lack of approval from its ally Syria, where some of the strikes are being carried out, and the United Nations.
"There is doubt over the legitimacy of the strikes as such actions can only be carried out with the approval of the United Nations and the unequivocal permission of the authorities of the country where they are taking place, which in this case is the government in Damascus," the Foreign Ministry said in a statement.
Russia has said air strikes against the radical Sunni group that has taken over wide swathes of territory in Iraq and Syria must be agreed with Damascus to avoid "fueling tensions."
Moscow has backed Syrian President Bashar al-Assad in his fight against rebels and sees his survival as a major foreign policy success. It now wants to see the West implicitly acknowledging his legitimacy by dealing with him directly.
Russia has not responded publicly to U.S. calls to build an international coalition to destroy Islamic State.
A Kremlin spokesman said President Vladimir Putin had discussed possible cooperation on countering Islamic State with "partners" as long as it was within the framework of international law.