BEIRUT, Lebanon — Russia is circulating a draft proposal to Syrian rebel groups and diplomats that envisions pausing the war in Syria through the creation of safe “de-escalation zones,” with outside troops possibly acting as buffers between the antagonists.

The draft proposal, shared with The New York Times on Wednesday by participants at Syria talks held in Astana, Kazakhstan, is one of the most detailed suggestions to emerge in recent months in the rocky negotiations to halt the war, now in its seventh year.

The proposal would apply to Syrian government and rebel forces in the four main areas of the country where insurgents unaffiliated with the Islamic State still hold significant territory.

But it faces a number of challenges, most notably acceptance by the Syrian government and the insurgent groups attending the talks.