MOSCOW: Russian Foreign Minister Sergey Lavrov said the United States should cooperate with Syrian President Bashar Assad to fight ISIS and that this required an international coalition uniting all those for whom the extremists are “a common enemy.”

Moscow has criticized the United States for not working in sync with Syria, an ally of Russia.

In comments to Russia’s state TV published by his ministry Sunday, Lavrov recounted two meetings with U.S. Secretary of State John Kerry amid the recent intensified high-level diplomatic contacts over Syria and fighting the Sunni extremists.

“Our American partners and some countries in the region persistently refuse to recognize Assad as a partner, which is rather strange,” Lavrov said. “Assad was a fully legitimate partner in destroying chemical arms but somehow he is not in fighting terrorism,” the foreign minister said, referring to a chemical disarmament deal brokered by Moscow and Washington earlier in the conflict.

Lavrov also warned against what he called unfounded claims that Syria has chemical weapons, as the United Nations Security Council investigates deadly chlorine gas attacks.

His comments came after Russia Friday backed the setting up of a U.N. Security Council panel to identify who is behind the chlorine attacks. Lavrov said the operation to remove chemical weapons from Syria was successful, and that all claims to the contrary should be checked.

A total of 1,300 metric tons of chemical weapons have been removed from Syria, with the majority being destroyed aboard the U.S. Navy ship MV Cape Ray.

“Sometimes publications come out that there could be undeclared chemical weapons in Syria. This is all being checked, here we must avoid unfounded accusations,” Lavrov said Sunday. “We have every basis to consider that Syria will continue cooperating closely.”

Lavrov Tuesday is set to meet his Saudi counterpart Adel al-Jubeir in Moscow to discuss the situation in Syria and Yemen and ways to combat ISIS. Lavrov stressed that international powers should unite against ISIS, calling it a “common enemy.”

He referred to a map drawn up by ISIS showing its plan to control the sites of Mecca and Medina in Saudi Arabia.

“Members of this terrorist organization have promised to blow up Muslim sacred sites because they consider them to be a reflection of ‘incorrect’ Islam. This is a terrible organization,” he said.

The main Western-backed Syrian opposition is due to visit Moscow next week. The National Coalition for Syrian Revolutionary and Opposition Forces (SNC) boycotted Syria peace talks held in Moscow in January and April, distrustful of Russia and critical of the Damascus rivals who attended, whom it described as token opposition. 

A Russian source familiar with preparations for the visit said an SNC delegation was due in Moscow Aug. 12 and 13 and would be led by its recently re-elected head, Khaled Khoja.

The source said they were due to meet Lavrov, his deputy and President Vladimir Putin’s special Middle East envoy, Mikhail Bogdanov, and Vitaly Naumkin, a Russian academic who served as moderator during two rounds of Syria peace talks in Moscow in January and April.

The source said the Russians next week will want to discuss with the SNC holding another round of Moscow consultations and will push the group to commit to taking part in those talks.