Smoke rises as seen from a rebel-held area of Aleppo, Syria December 12, 2016.

:: An open-ended cease-fire in southern Syria brokered by the United States and Russia has come into effect.

The ceasefire, announced after a meeting between US President Donald Trump and Russian President Vladimir Putin in Hamburg last week, is the first initiative by the Trump administration in collaboration with Russia to bring some stability to war-torn Syria

No ceasefire has lasted long in the six-year-old Syrian war. US-backed rebels, Syrian government forces, and ISIS militants are all fighting for control of southern Syria.

The latest truce, which began at noon (0900 GMT) Saturday, is intended to allay concerns of neighboring Israel and Jordan about Iranian-backed and government-allied forces at their borders. The truce does not include ISIS.

“At noon local time tomorrow, a de-escalation zone in southwest Syria will begin to take effect,” Trump’s national security adviser HR McMaster said in a statement released Saturday.

“Such zones are a priority for the United States, and we’re encouraged by the progress made to reach this agreement,” he 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,” he said.

The decision to impose a ceasefire zone, announced Friday at the summit by Moscow’s Foreign Minister Sergei Lavrov, was reached with the US, Russia and Jordan.

Russia, an ally of Syrian President Bashar al-Assad, has been engaged in talks this year with Turkey and Iran over four so-called de-escalation zones in the war-torn country.

Lavrov said the ceasefire would be supervised by Russian military police “in coordination with the Jordanians and Americans.”

Syria’s conflict evolved from a bloody crackdown on protests in 2011 to a devastating war that has drawn in world powers, including Russia and the US-led international coalition.

More than 320,000 people are estimated to have been killed and millions have been displaced.

US President Donald Trump shakes hands with US Army Lieutenant General H.R. McMaster (L) as his national security adviser at his Mar-a-Lago resort in Palm Beach, Florida.