Syria's Islamist-led government said its security forces were deploying in the predominantly Druze southern city of Sweida on Saturday, and urged all parties to respect a ceasefire after days of factional bloodshed that has left hundreds dead.

Interim President Ahmed al-Sharaa, in a separate speech, said "Arab and American" mediation had helped bring calm, and criticized Israel for airstrikes against Syrian government forces in the south and Damascus this week.

Sweida province has been engulfed by nearly a week of violence, which began with clashes between Bedouin fighters and Druze factions, before Damascus sent in government security forces.

Israel has carried out airstrikes in southern Syria and on the Defence Ministry in Damascus, saying it is protecting the Druze minority, of whom there are a significant number in Israel and the Israeli-occupied Golan Heights.

In a statement on Saturday, the Syrian presidency announced an immediate and comprehensive ceasefire, and urged all parties to end hostilities immediately.

The Interior Ministry said internal security forces had begun deploying in Sweida.

Sharaa called for calm and said Syria would not be a "testing ground for partition, secession or sectarian incitement."

"The Israeli intervention pushed the country into a dangerous phase that threatened its stability," he said in a televised speech.

U.S. envoy Tom Barrack announced on Friday that Syria and Israel had agreed to a ceasefire supported by Turkey, Jordan and neighbours.

Barrack, who is both U.S. ambassador to Turkey and Washington's Syria envoy, urged Druze, Bedouins and Sunnis to put down their weapons "and together with other minorities build a new and united Syrian identity."

Israel has attacked Syrian military facilities and weaponry in the seven months since Sharaa's forces toppled President Bashar al-Assad, and says it wants areas of southern Syria near its border to remain demilitarized.

On Friday, an Israeli official said Israel had agreed to allow Syrian forces limited access to the Sweida area for the next two days.