Iraqi forces battling jihadists on several fronts Thursday were poised to receive the help of 450 extra US troops slated for deployment near Ramadi.

In neighbouring Syria, a rebel alliance that includes groups supported by Washington, seized most of a military airport in a southern province controlled by the regime, a spokesman said.

State television denied the claim but both the Southern Front and a monitoring group said the regime had lost most of Al-Thaala airport in Sweida province.

They also said the rebels shot down a Syrian warplane. State TV acknowledged that an aircraft went down and said an investigation was under way.

Washington's decision to send more advisers and trainers to Iraq has failed to silence critics who say the White House lacks a strategy to combat the Daesh group.

A year after a jihadist offensive saw the government lose swathes of Iraq, military operations to weaken Daesh were experiencing mixed fortunes.

The autonomous Kurdistan region's peshmerga forces pushed south and west of Kirkuk on the back of intensive bombing by Iraqi and US-led coalition warplanes, security officials said.

One of the targets was a bomb-making workshop Daesh had set up after their main car bomb factory in nearby Hawijah was completely levelled in a coalition air strike, one official said.

The June 3 strike caused an explosion that was heard 50 kilometres (30 miles) away and destroyed what some officials said was Daesh' largest such plant in Iraq and Syria.

Federal troops and the Popular Mobilisation -- an umbrella for mostly Shiite militias and volunteers -- also continued operations aimed at securing Baiji, north of Baghdad.

The area has seen relentless fighting over the past year and loyalists in recent days achieved some progress in pushing Daesh fighters out of the town of Baiji as well as from the nearby refinery, the country's largest.

- Baiji fighting -

Anti-IS forces launched a wide-ranging military operation early Thursday to clear "the last Daesh pockets along the Tigris River" around Baiji, an army major general said.

Establishing firm control over Baiji is seen as key to isolating Daesh in the vast western province of Anbar, whose reconquest is Baghdad's declared priority.

The jihadists beat the government to the punch, seizing provincial capital Ramadi on May 17 and dealing Baghdad its worst setback in almost a year.

Prime Minister Haider al-Abadi vowed to swiftly retake Ramadi but operations have been sluggish and questions are still being asked about the security forces' ability following their chaotic retreat from the city.

On Wednesday, US President Barack Obama approved the deployment of 450 more troops to Iraq, in what would nudge the ranks of Washington's "train, advise and assist" mission above 3,500.

The new contingent will be based at Taqaddum Air Base, nestled along the Euphrates River between jihadist-held Ramadi and Fallujah.

"There is always a risk whenever we're in Iraq that we could be hit with indirect fire, as we have in the past, that we could be attacked," said senior Pentagon official Elissa Slotkin.

The fall of Ramadi last month was not just a blow to Baghdad but also to Washington's strategy in tackling an ultraviolent group whose appeal has kept growing, making it a global threat.

The US-led coalition has carried out close to 4,500 air strikes since August and undertaken training to reform a security apparatus that completely folded when Daesh swept in a year ago.

- US strategy -

Obama, who admitted the United States did not "yet have a complete strategy," has come under intense criticism for allowing chaos to spiral in the region.

"I support the tactical move the president is taking, but where's the overarching strategy," asked House of Representatives Speaker John Boehner, reacting to the announcement on the latest reinforcements.

The Soufan Group risk consultancy said seven years of US military presence following the 2003 invasion and billions of dollars invested in training and equipment had not prevented disaster.

"The logistics, non-commissioned officer cadre, and command and control that effective militaries depend upon were always missing from the new Iraqi army," it said.

Several officials in Anbar said Thursday that Iraqi and foreign warplanes had bombed targets in and around Ramadi.

Kurdish fighters also backed by coalition warplanes took the town Suluk in northeastern Syria and advanced towards the Daesh-held town of Tal Abyad, Syrian Observatory for Human Rights said.

The monitoring group said fighters from the Kurdish People's Protection Units (YPG) "plan to lay siege to Tal Abyad," which lies on the border with Turkey.
Source: AFP