The United States and Russia have hailed a breakthrough deal to put Syria’s peace process back on track.

After a day of marathon talks in Geneva, US Secretary of State John Kerry and Russia’s Foreign Minister Sergei Lavrov announced the truce, which is set to come into force on Monday (local time), the first day of the Muslim holiday of Eid.

The deal includes a nationwide ceasefire effective from sundown on Monday, improved aid access and joint targeting of banned Islamist groups.

Mr Kerry said he believed the plan would lead to talks to “stop the conflict” which has raged for more than five years, killing more than 290,000 people and displacing millions.

Under siege: Syrian city of Aleppo. Photo: AAP

“Today, Sergei Lavrov and I, on behalf of our president and our countries call on every Syrian stakeholder to support the plan that the United States and Russia have reached, to … bring this catastrophic conflict to the quickest possible end through a political process,” Mr Kerry said on Saturday.

Mr Lavrov said that despite continuing mistrust, the two sides had developed five documents that would enable co-ordination of the fight against terrorism and a revival of Syria’s failed truce in an enhanced form.

“This all creates the necessary conditions for resumption of the political process which has been stalling for a long time,” Lavrov told a news conference.

Mr Kerry said the “bedrock” of the deal was an agreement that the Syrian Government would not fly combat missions in an agreed area, on the pretext of hunting fighters from the banned Nusra Front, an Al Qaeda affiliate in Syria.

“That should put an end to the barrel bombs, and an end to the indiscriminate bombing, and it has the potential to change the nature of the conflict,” he said.

Mr Lavrov said if the ceasefire lasted a week, US and Russian forces would carry out joint air strikes to target the Nusra Front and Islamic State (IS) groups.