The White House has warned that the US and its allies would respond "swiftly and vigorously" if government forces used chemical weapons in Idlib.
Moscow's accusation comes after Washington said it will respond "very strongly" if Syrian President Bashar al-Assad uses chemical weapons in an offensive to retake Idlib.
US officials say they have information Assad may be planning a chemical attack in the northwestern province of Idlib.
The three UN Security Council powers released the joint statement to mark the fifth anniversary of the sarin attack in Ghouta that killed more than 300 people.
There would be further negotiations on a deadline for handing over medium and heavy weapons, according to the agreement sent by the rebel source.
Israel worries Assad could let his Iranian and Hezbollah reinforcements entrench near Israeli lines or that Syrian forces may defy a 1974 Golan demilitarisation.
Israel's remarks could foreshadow a more open approach to Assad ahead of Israeli Prime Minister Benjamin Netanyahu's Syria talks with Russian President Vladimir Putin in Moscow on Wednesday.
The rebels said the deal was brokered by Russia and would allow both fighters and civilians in opposition areas to settle their status with the government under Moscow's protection.
Turki berkata usaha damai mustahil diteruskan dengan seorang presiden yang membunuh hampir sejuta rakyat sendiri.
Usaha pemberontak mempertahankan gencatan memulihkan harapan perang hampir 6 tahun itu akan dapat ditamatkan.