On Saturday, the US-led coalition conducted airstrikes on Syrian army positions in Deir ez-Zor, killing scores of soldiers. The Pentagon claimed that the attack was unintentional.
There is "very little" hope that the Russian-US week-long ceasefire in Syria will resume, Peskov said, naming two conditions to resume the truce.
"It is very simple: the terrorists need to stop attacking the Syrian armed forces. And of course it would not hurt if our US colleagues did not accidentally bomb Syrians," Peskov stressed.
The United States has failed to deliver on its written pledge to separate armed opposition forces from terrorists in Syria, Peskov said.
"We understand that such actions threaten the entire process in general, and note with regret that during this period that has already exceeded one week, our US colleagues failed to carry out the disengagement of terrorists from the so-called moderate opposition," Peskov said.
US claims of Russia being behind shelling of a UN humanitarian aid convoy on its way to the Syrian city of Aleppo are "mere allegations," Peskov said Tuesday.
"I do not think it possible and proper to make any unsubstantiated conclusions. Currently our military is assessing the information about this shelling, and I hope they will receive specific information from primary sources and will be able to make a corresponding statement."