Syria's foreign minister is to address the summit of world leaders at the United Nations General Assembly on Friday as Russia's decision to start bombing targets in the war-torn nation adds another layer of tensions to the region.

The Kremlin says it is acting on request of the Syrian government of President Bashar Assad. The United States opposes Assad and has questioned Moscow's assertion that it is targeting Islamic terrorists, saying the areas hit close to Homs are strongholds of the moderate opposition to Assad.

As Russian war planes bombed Syria for the second day Thursday, Foreign Minister Sergey Lavrov rejected claims that Moscow is targeting those moderates, the opposition Free Army.