A ceasefire deal hammered out between Moscow and Washington that could have led to the two countries coordinating strikes on jihadists has unravelled in acrimony, with both sides blaming each other for the failure.
Russia is backing up a ferocious assault by the forces of Syria's President Bashar al-Assad to seize the rebel-held eastern half of the city of Aleppo that has sparked condemnation from the West.
"We have unfortunately taken note of the rather unconstructive character of the rhetoric from Washington over the past few days," Peskov said.
"Moscow maintains its interest in cooperating with Washington for the realisation of the agreement."
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In the meantime, Peskov said "Moscow is continuing its air operation to support the anti-terrorist actions of the Syrian armed forces."
US Secretary of State John Kerry told his Russian counterpart Sergei Lavrov on Wednesday that possible plans to set up a joint US-Russia military cell to target jihadist groups in Syria could also be put on hold.
Moscow was to order its ally Syrian leader Bashar al-Assad to rein in his military and end the bombardment of civilian communities, and Washington was to persuade rebel forces to separate themselves from the jihadist Fateh al-Sham, the former Al-Qaeda affiliate once known as Al-Nusra Front.
But fighting continued and the truce collapsed.
In Moscow, the defense ministry said Wednesday that it was "ready to continue joint work with our American partners on the Syrian issue" but gave no sign that Russia is ready to ground the Syrian air force.