Deal to support Kurds in exchange for key cities set to open new front in civil war

• What is the situation in north-eastern Syria?

Syrian troops have begun sweeping into Kurdish-held territory on a collision course with Turkish forces and their allies, a day after the beleaguered Kurds agreed to hand over key cities to Damascus in exchange for protection.

The deal, which Kurdish leaders emphasised they had made reluctantly after four days of bombardment by Turkish artillery and jets, threatens to open a new front in Syria’s nearly nine-year civil war, and signals the likely end of US and European military deployments in the country’s north-east.

Rebels shot at least nine civilians in execution-style killings in Syria, according to Syrian Observatory for Human Rights

Pro-Ankara fighters taking part in a Turkish offensive on Kurdish-held border towns in north-eastern Syria have killed at least nine civilians including a female politician, a human rights monitor has said.

“The nine civilians were executed at different moments south of the town of Tal Abyad,” the Syrian Observatory for Human Rights said.

Martin Chulov reports from north-east Syria on the deadliest day yet of the Turkish offensive

In a wooden hut at the back of a hospital, a woman cradled the head of a dead man and dabbed away grime and blood with a sponge. A blanket covered the man’s mutilated lower half. His blood-soaked military fatigues were still wrapped around his chest.

On a table behind, another body lay zipped into a large blue bag – a young woman this time, also dressed in green and wearing the patches of Kurdish forces. The medical worker straightened her head and gently swept the dead woman’s hair from her face. “We have five martyrs now,” she said, pointing across the makeshift morgue. “Three military and two civilians. The fighters were trying to rescue the others.”

Border residents feel the impact as fighting between Turkish and Kurdish forces escalates

On Wednesday, children in the Turkish town of Akçakale were happy to get a day off from school in honour of the launch of Operation Peace Spring aimed at Kurdish forces over the nearby border with Syria. They ran around the streets singing army songs and waving Turkish flags. “Get out of our way,” tabloid headlines read.

By Thursday the mood had changed drastically. Akçakale’s streets were dark with smoke from mortar and rocket fire after the Kurdish-led Syrian Democratic Forces (SDF) launched a ferocious counter-attack from Tal Abyad, just over the border.

There were signs of panic in Ras al-Ayn on Wednesday after Turkish forces launched an offensive into northern Syria. The move was triggered by Donald Trump's announcement that US troops would withdraw from the area, where thousands of captured Isis fighters and their families are held by Kurdish forces

• Turkey launches military operation in northern Syria