A member of the US-backed Syrian Democratic Forces removes an Islamic State group flag in the town of Tabqa on April 30, 2017
Beirut (AFP) - US-led warplanes hit a pro-regime convoy in Syria that ignored warning shots, weeks after President Donald Trump's administration launched America's first strikes against Damascus forces in the war-torn country.
The strike by the coalition fighting the Islamic State group happened on the same day IS jihadists killed more than 50 people in attacks on two government-held villages elsewhere in the country.
It came as the United Nations said Syria's regime and rebels had agreed to set up expert committees to discuss "constitutional issues" at the latest round of UN-backed peace talks in Geneva.
US-led aircraft struck the convoy as it headed toward a remote coalition garrison near the border with Jordan, a US defence official said.
"A convoy going down the road didn't respond to numerous ways for it to be warned off from getting too close to coalition forces in Al-Tanaf," the official told AFP on condition of anonymity.
"Then there was finally a strike against the lead portion of that movement."
The coalition said the strike had occurred "well inside" an established de-confliction zone northwest of the Al-Tanaf garrison, where British and US commandos have been training and advising local forces fighting IS.
Pentagon chief Jim Mattis said, despite the strikes, the United States was "not increasing our role in the Syrian civil war, but we will defend our troops".
The Syrian Observatory for Human Rights monitor said the strikes killed eight people "most of them non-Syrian" and destroyed four vehicles.
The United States has been militarily involved in Syria since 2014, but has for the most part avoided engaging directly in the conflict.
But last month, it launched a barrage of missiles at Syria's Shayrat airbase, which it said was the launchpad for an alleged chemical attack that killed dozens of civilians.
- IS executions -
Also on Thursday, IS killed more than 50 people in an attack on two regime-held villages in the central province of Hama, said the Observatory.
The attack on the villages of Aqareb and Al-Mabujeh killed at least 15 civilians and 27 pro-government fighters, it said.
Another 10 bodies were yet to be identified.
IS also lost 15 fighters in the dawn attack on the villages in the east of the province, said the monitor.
Observatory director Rami Abdel Rahman said at least three of the civilians were killed execution style with knives, a man and his two children.
State media also reported 52 people had been killed in the IS assault, though it described the attack as against Aqareb only.
It said IS fighters had mutilated the bodies of villagers and looted their homes, and said 15 of the dead were children.
The Observatory said IS had seized control of Aqareb and part of Al-Mabujeh in the attack, which began with heavy shelling on a nearby regime checkpoint.
"Despite the arrival of reinforcements, government forces have been unable to repel the attack so far," said Abdel Rahman.
IS has attacked Al-Mabujeh before with devastating effect.
In March 2015, it executed at least 37 civilians in the village, whose population includes Sunnis as well as those from the Ismaili sect and the Alawite community to which President Bashar al-Assad belongs.
During the same assault the group kidnapped at least 50 civilians, half of them women.
Control of Hama province is divided between the government, rebel forces and IS, which is present mostly in the east of the area.
- UN-backed talks -
IS faces pressure in northern Syria, where an alliance of Kurdish and Arab fighters is preparing an assault on its bastion Raqa city.
The battle for Raqa has stirred tensions with neighbouring Turkey, which is fiercely opposed to the Kurdish fighters now leading the operation to capture the city.
On Thursday, Turkish Foreign Minister Mevlut Cavusoglu called for the removal of US diplomat Brett McGurk, who coordinates the US-led coalition against IS, saying he was supporting the Kurdish fighters.
More than 320,000 people have been killed in Syria since the conflict began with anti-government demonstrations in 2011.
The conflict has proved stubbornly resistant to international efforts to find a political solution, but a new round of UN-sponsored talks are underway this week in Geneva.
But the United Nations said Thursday the warring sides had agreed to set up expert committees to discuss "constitutional issues".
A new constitution is one of four separate "baskets" on the agenda at the talks, along with governance, elections and combating "terrorism".
The UN-sponsored process has been somewhat overshadowed by a parallel track convened in Kazakh capital Astana by regime supporters Russia and Iran along with rebel backer Turkey.
The three nations agreed earlier this month to establish four "de-escalation zones" in Syria, and are now hammering out the details of the plan.