The United States has provided Syrian fighters battling the Islamic State group with armoured vehicles for the first time, a US official and a spokesman for the anti-jihadist force said Tuesday.

The delivery appears to be the first under President Donald Trump's administration, though the original decision pre-dates his January 20 inauguration, and comes after he gave the US military 30 days to deliver a plan to "defeat" IS.

Washington has long partnered with the Kurdish-Arab Syrian Democratic Forces alliance to battle IS in Syria, which has been ravaged by conflict since an anti-government uprising that began in March 2011.

But SDF spokesman Talal Sello said Trump's administration had now promised "extra support".

US military spokesman Colonel John Dorrian said the armoured Sports Utility Vehicles had been provided to the "Syrian Arab Coalition", a grouping of Arab factions within the SDF.

He told AFP the decision was made "using existing authorities, in the interest of helping protect our partnered force from the (IS) improvised-explosive device threat."

"The decision was made by military commanders, and has been in the works for some time," he added.

The SDF has been a key partner for the United States in the fight against IS in Syria, with Washington supplying light weapons and special forces military advisers during former president Barack Obama's administration.

The US-led coalition fighting IS in Syria and Iraq has also carried out air strikes in support of the SDF as it battles IS.

- 'A new phase' -

Pentagon spokesman Eric Pahon said the decision to supply the vehicles pre-dated the Trump administration, but on the ground it was being interpreted as a sign of new support.

"Before we used to receive light weapons, ammunition... with these armoured vehicles we've entered a new phase in the (US) support. It's a sign," Sello added.

"We have had meetings with representatives of the new administration, and they promised us extra support."

The US alliance with the SDF has caused tensions between the United States and Turkey.

Of the roughly 30,000 fighters within the coalition, around two-thirds belong to the Kurdish People's Protection Units (YPG), which Turkey considers a "terrorist" group.

Washington insists it only delivers military aid to the Arab component of the SDF, but the assistance has angered Ankara nonetheless.

Pahon said the decision to supply the vehicles "was a ground-level tactical decision... based on the threats the SDF might be facing."

"We are providing them with the tools to face whatever the current threat is."

The SDF has been battling since November 5 to oust the jihadists from Raqa city, the group's de facto capital in Syria.

They are 20 kilometres (12 miles) north of the city, but have come under frequent attack by IS suicide car bombers, a favoured tactic of the jihadist group.

- UN-led peace talks delayed -

The SDF was formed in October 2015, after the YPG Kurdish militia had already scored victories against IS in northern Syria with air support from the US-led coalition.

Elsewhere in Syria on Tuesday, at least 30 IS fighters were killed in a series of air strikes over several hours in Aleppo province, the Syrian Observatory for Human Rights said. 

The Britain-based monitor could not determine if the strikes, near the Kweyris military airport east of Aleppo city were carried out by Syrian warplanes or those of its ally Russia. 

Trump has said his focus in Syria will be battling IS, and on Saturday he signed an executive order giving the US military 30 days to devise a plan to "defeat" the jihadist group.

The order, which called for a "comprehensive strategy and plans for the defeat of ISIS", was seen as meaning more US forces and military hardware moving into Iraq and Syria.

More than 310,000 people have been killed in Syria since the conflict began, and successive rounds of international efforts to find a political solution to the war have failed.

On Tuesday, the UN's special envoy on Syria, Staffan de Mistura, said a new round of UN-led peace talks originally scheduled for February 8 had been postponed to February 20.

He said the delay would give the Syrian opposition more time to prepare and ensure the talks are as inclusive as possible, two diplomats told AFP.

The delay comes after peace talks in Kazakh capital Astana, sponsored by Syrian government allies Russia and Iran and rebel backer Turkey, ended with no major progress.

Trump's administration was invited to participate in the talks but did not send a delegation.

Source: AFP