The United Nations Security Council is set to vote on September 19 on rival draft resolutions calling for a truce in northwest Syria.
The council is set to decide between a resolution submitted by Kuwait, Germany, and Belgium and a rival draft put forward by Russia and China.
The resolution by Kuwait and the European countries calls for the Security Council to demand all sides "immediately cease hostilities" in Syria's Idlib Province.
It calls for a cease-fire to begin at noon local time on September 21 and says it would help "avoid a further deterioration of the already catastrophic humanitarian situation in Idlib."
Diplomats have told Reuters that Moscow wants language included that would exempt from the truce any military actions against armed groups blacklisted by the Security Council.
The United States and others have refused Moscow's demand, diplomats said. The draft instead insists that "member states ensure that all measures taken to counter terrorism, including in Idlib Governorate, comply with their obligations under international law."
Washington and other Western states have accused Moscow and allied Syrian forces of targeting civilians in Idlib.
Russia and Syria deny the charge, claiming they have targeted militants, including the Nusra Front, an extremist group also known as Hayat Tahrir al-Sham that has been linked to Al-Qaeda.
Russia and China put forward a separate text to the UN that "reaffirms that the cessation of hostilities shall not apply to military operations against individuals, groups, undertakings and entities associated with terrorist groups, as designated by the Security Council," according to a text seen by Reuters.
A deal was struck in September with the aim of averting a full-scale regime offensive on Idlib Province and nearby areas held by Hayat Tahrir al-Sham.
But Syrian President Bashar al-Assad's regime and its Russian ally have since late April ramped up deadly air strikes and rocket fire on the militant stronghold, and fighters have clashed on its edges.
According to the UN, since the start of hostilities in northwest Syria in April, more than 550 civilians have been killed and some 400,000 people have been displaced.
Russia and Iran have provided crucial support for Assad during the long, bloody civil war, while the United States and Turkey have backed differing rebel groups fighting the central government.
Islamic State (IS) and other extremist groups also entered the civil war and were opposed by all other sides.
More than 400,000 people have been killed and millions have been displaced since the war began in March 2011 after a crackdown on anti-Assad protests.