A ceasefire brokered by the US, Russia and Jordan began in south-west Syria on Sunday, in the latest attempt at international peacemaking during the six-year war.

The proposal was announced at the G20 summit on Friday, after a two-and-a half-hour meeting between President Trump and Russian President Vladimir Putin.

Lt Gen HR McMaster, the White House national security adviser, said: “The United States remains committed to defeating Isis, helping to end the conflict in Syria, reducing suffering and enabling people to return to their homes.

“This agreement is an important step toward these common goals.”

The agreement could be the forerunner to continued cooperation in Syria, said US Secretary of State Rex Tillerson, who was present at the meeting between Trump and Putin, according to CNN.

Sergei Lavrov, Russia’s foreign minister added: “This is our first indication of the US and Russia being able to work together in Syria.”

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Russian military police, together with the US and Jordan, will ensure security around the de-escalation zone, officials said. The truce will be monitored through satellite and drone images as well as observers on the ground, according to a Jordanian official.

The ceasefire began at midday (09:00 GMT) on Sunday, in the areas of Deraa, Suweida and Quneitra in the south-west, as well as along the Lebanese border.

The Syrian Observatory for Human Rights said “calm was prevailing” in the area, reporting that there have been no air strikes or clashes since the ceasefire began.

Precise details of the ceasefire have not been made public, but the UK-based human rights organisation cited “credible sources” saying that the agreement provides for the withdrawal of non-Syrian fighters allied with al-Assad’s regime from the truce area.

The London-based monitor also hopes that humanitarian aid deliveries can get through to the ceasefire region, and aims for the gradual repatriation of Jordanian refugees.

A rebel official in Deraa city also added that there had been no significant fighting, according to Reuters.

Similar truces have been negotiated in Syria previously, to continue talks ending the civil war which began in 2011. So far, all have failed.