Russia’s Deputy Foreign Minister Sergei Ryabkov called the proposal "not functional" and denied that his country had carried out the fatal attack on a United Nations aid convoy in Aleppo on Monday.
Ryabkov said "the chance of a deal between Russia and the U.S. was lessened" following the U.S. airstrike last week on the Syrian army and this week's bombing of Syrian aid trucks, carried out by either Syrian or allied Russian warplanes.
He added that Moscow’s priority is to solve the Syrian crisis through political means.
The attack on the aid convoy came on the same day as the Syrian military announced that a one-week truce brokered by the U.S. and Russia was over.
On Wednesday, U.S. Secretary of State John Kerry criticized what he called Russia and Syria's attack on civilians and aid workers and told the UN Security Council that flights in the region should be banned from allowing aid flow into the country.
Kerry proposed that the way forward "out of the carnage" would be a ban on Syrian government forces flying over areas controlled by the opposition.
According to Kerry, Syrian regime is hitting opposition groups under the cover of fighting against extremist groups.
Kerry's calls to ground flights come weeks after the U.S. defense department said it wanted less flights in the region, but refused to call it a no-fly zone.