The "de-escalation zones" to be established in Syria will be closed to military aircraft from the US-led coalition, the Russian official who signed the new agreement said.
Alexander Lavrentyev spoke a day after he and officials from Turkey and Iran agreed to establish the zones, in the latest attempt to reduce violence in the Arab country.
Under the Russian plan, President Bashar Assad's air force would halt flights over the designated areas.
Mr Lavrentyev suggested that all military aircraft, including Russian and Turkish, also were prohibited.
The same was suggested in a UN statement, which said Secretary-General Antonio Guterres "welcomes the commitments to ceasing the use of all weapons, particularly aerial assets".
Full details of Thursday's agreement have not yet been released. The Russian Defence Ministry said it would do so later.
Mr Lavrentyev, whose remarks were carried by Russian news agencies, said: "The operation of aviation in the de-escalation zones, especially of the forces of the international coalition, is absolutely not envisaged, either with notification or without. This question is closed."
He said the US-led coalition aircraft would still be able to operate against Islamic State in specific areas.
As the agreement was being signed in Astana, the capital of Kazakhstan, some members of the Syrian opposition delegation shouted in protest and walked out.
The opposition was protesting against Iran's participation at the conference and role as a guarantor of the agreement.
They accuse it of fuelling the sectarian nature of the conflict that has killed some 400,000 people and displaced half the country's population.
The walkout and comments underline the huge difficulties of implementing such a deal.
The Syrian government has said that although it will abide by the agreement, it would continue fighting "terrorism" wherever it exists, parlance for most armed rebel groups fighting government troops.
A previous ceasefire agreement signed in Astana on December 30 helped reduce overall violence for several weeks but eventually collapsed. Other attempts at a ceasefire in Syria have all ended in failure.
Sponsors of the deal hope that safe zones would bring relief for hundreds of thousands of Syrian civilians and encourage refugees to return.
But officials have expressed scepticism, stressing that safe zones have not had an encouraging track record.