MOSCOW - The international community will struggle with the Islamic State (IS) more efficiently if Western countries and their partners stop demanding the resignation of Syrian President Bashar al-Assad, Russian Foreign Minister Sergei Lavrov said Tuesday.

"If we remove from the equation the entirely unrealistic and counterproductive demand of the resignation of Assad as a precondition for the fight against terrorism... we may work effectively," Lavrov was quoted as saying by RIA Novosti news agency.

Russia's top diplomat said he was puzzled by the Western claim that only when the Syrian authorities agreed to destroy the country's chemical weapons could they be considered as a legitimate partner.

"It simply cannot be that, for the purpose of the destruction of chemical weapons Assad is legitimate, and for the purpose of fighting against terrorism he is not. It is not logical," Lavrov said.

Moscow insists that the resolution of the Syrian crisis should include all forces capable of resisting the IS. In June, Russian President Vladimir Putin proposed to establish an international framework to create a coalition on fighting regional terrorism.

The anti-IS coalition implies that the Syrian and Iraqi army as well as their militia of the Kurds, along with forces of the Syrian opposition, which consist of Syrian citizens instead of mercenaries, will make concerted efforts and coordinate their actions, Lavrov specified.

"The main thing is that the forces opposing the Islamic State do not interfere with each other," he said.(Xinhua)