Russian Foreign Minister Sergei Lavrov is to host UN envoy Staffan de Mistura for talks on Syria in Moscow on Tuesday, the foreign ministry said.

"Talks between Mistura and Sergei Lavrov followed by a press conference will take place" in Moscow, spokeswoman Maria Zakharova told AFP on Monday.

The talks will be held amid accusations by the United States and other supporters of the Syrian opposition that Russia has violated international agreements to back peace in the war-torn country.

Washington and Moscow are the joint sponsors of the Syrian peace process, and de Mistura had made it clear that he sees little hope of progress without their agreement.

But the United States charges that Russia, while agreeing to support a ceasefire, has done little to rein in Syrian President Bashar al-Assad's forces around Aleppo.

The head of Moscow's coordination centre in Syria, Lieutenant General Sergei Kuralenko, said on Sunday that talks to include Aleppo province in a so-called "regime of silence" -- or freeze in fighting -- had begun.

Kuralenko told reporters on Monday that those talks were still continuing.

Russia says it will not ask the Syrian regime to halt air raids on Aleppo as it believes they are helping to combat jihadist groups there.

More than 270,000 people have been killed since Syria's conflict erupted in March 2011 with protests demanding Assad's ouster.

Source: AFP