Moscow, Russia: Russian Foreign Minister Sergei Lavrov on Friday called for cooperation to prevent Islamic State jihadists from leaving Mosul and heading to Syria during the offensive under way to recapture the Iraqi city.

"We are interested in cooperation with our Iraqi colleagues to take measures to prevent the outflow of terrorists from Mosul with their weapons, which of course will exacerbate the situation in Syria," Lavrov said following talks in Moscow with his Iranian and Syrian counterparts Mohammad Javad Zarif and Walid Muallem. 

"We will discuss this with the United States and other members of the coalition," he said.

The offensive to recapture Iraq's second city, launched on October 17 and backed by a US-led coalition, is seeing tens of thousands of Iraqi troops advance on Mosul in a bid to retake the last major Iraqi city under IS control.

Russia's defence ministry last week urged the coalition not to "drive terrorists" from Iraq to Syria during the offensive, warning it of the risk of "freely roaming" IS jihadist gangs.

The United States said Thursday that up to 900 IS jihadists have been killed in the offensive so far as Iraqi forces allied with Kurdish peshmerga fighters have taken a string of towns and villages in a cautious but steady advance.

Western leaders have meanwhile accused Moscow of committing possible war crimes in the Syrian city of Aleppo through indiscriminate bombing in support of a brutal government offensive to retake the city's rebel-held east.

The Russian defence ministry has said that neither Syrian nor Russian warplanes have bombed Aleppo for 10 days.

Russia has meanwhile denied any role in deadly air strikes on a Syrian school in the rebel-held province of Idlib that killed 22 children.

According to the Syrian Observatory for Human Rights, the strikes had been carried out by "warplanes -- either Russian or Syrian."

Lavrov on Friday repeated Moscow's denial of involvement in the attack, saying that the defence ministry has published "information with facts that refute these claims and show the fabricated nature of this disinformation."