Four US personnel killed in Syria suicide attack

IS claims attack on cafe in Manbij city

A suicide attack killed four US personnel in northern Syria Wednesday, costing Washington its worst combat losses in the war-torn country since 2014 as it prepares to withdraw.

The bombing, claimed by the militant Islamic State group, comes after US President Donald Trump's shock announcement last month that he was ordering a full troop withdrawal from Syria because IS had been "largely defeated".

The Pentagon said "two US service members, one Department of Defense (DoD) civilian and one contractor supporting DoD were killed and three service members were injured while conducting a local engagement in Manbij".

Turkey to set up Syria 'security zone' after Trump call

"Initial reports indicate an explosion caused the casualties, and the incident is under investigation," it said, adding that the names of the dead were being withheld until 24 hours after their families were informed.

The Syrian Observatory for Human Rights earlier said two Americans soldiers, nine Syrian civilians, and five US-backed fighters were killed in the attack on a restaurant in the northern city of Manbij near the Turkish border.

Rubble littered the outside of the eatery in the city centre and its facade was blackened by the blast, footage from a Kurdish news agency showed.

According to Pentagon statistics, Wednesday's blast was the deadliest attack for US anti-IS forces in Syria since they deployed in 2014.

The US Department of Defense has previously only reported two American personnel killed in combat in Syria, in separate incidents.

The Britain-based Observatory, which relies on a network of sources in Syria, said it was the first suicide attack in the city in 10 months.

'Security zone'

Addressing a gathering of US ambassadors in Washington, Vice President Mike Pence did not comment on the attack, saying only that the United States would ensure the defeat of IS.

"We'll stay in the region and we'll stay in the fight to ensure that IS does not rear its ugly head again," he said.

Iran says US troop presence in Syria 'wrong' from start

The bombing comes as Syrian Kurds present in areas around Manbij rejected any Turkish presence in a planned "safe zone" to include Kurdish-held areas along the frontier.

Turkey has repeatedly threatened to attack Washington's Syrian Kurdish allies, who Ankara views as "terrorists" on its southern flank.

Washington, which has relied heavily on the Kurds in its campaign against IS in Syria, has sought guarantees for their safety since Trump's pullout announcement.

On Tuesday, Turkey's President Recep Tayyip Erdogan said Ankara would set up a "security zone" in northern Syria following a suggestion by Trump.

But senior Syrian Kurdish political leader Aldar Khalil said any Turkish deployment in Kurdish-held areas was "unacceptable".

He said the Kurds would accept the deployment of UN forces along a separation line between Kurdish fighters and Turkish troops.

But "other choices are unacceptable as they infringe on the sovereignty of Syria and the sovereignty of our autonomous region," Khalil told AFP.

The Kurdish People's Protection Units (YPG) have been a key US ally in the fight against IS.

Ankara has welcomed Washington's planned withdrawal of some 2,000 US troops from Syria, but the future of Kurdish fighters has poisoned relations between the NATO allies.

On Monday, Erdogan and Trump had a telephone conversation to ease tensions after the US leader threatened to "devastate" Turkey's economy if Ankara attacked Kurdish forces in Syria, and called for a "safe zone".