A representative of the Combined Joint Task Force-Operation Inherent Resolve, said that neither the United States nor its allies coordinated with Russia while conducting operations against Islamic State group militants in Syria and Iraq.

Captain Nikolaj Thide told Russia's Tass news agency that U.S. authorities did not coordinate combat activities with their Russian counterparts. His remark comes after Washington said it would welcome Russia to contribute constructively to the fight against ISIS militants. However, the U.S. administration is strongly against Russia providing any form of support to the Assad regime.

The U.S., meanwhile, said that Russia appears to have plans to establish a "forward air operating base" in Syria. According to Pentagon spokesman Jeff Davis, Russia has been steadily sending equipment and people near Syria's city of Latakia.

"We have seen indications in recent days that Russia has moved people and things into the area around Latakia and the air base there that suggests that it intends to establish some sort of a forward air operating base," BBC quoted Davis as saying.

Russian Foreign Minister Sergei Lavrov said Sunday that Russia would sent specialists to Syria to train government forces on how to use supplied weapons.

"Over all these years, from the very beginning of the Arab Spring, from the time it degraded into development of terrorists and extremists, who began overthrowing regimes in various countries and began being supported by those who also shared negative attitudes to the former leaders, we have been declaring we shall help the Syrian authorities, like we have been assisting Iraq and governments of other countries, which are facing the terrorist threat," Lavrov said.