Air strikes pound south-west Syrian city of Deraa

WASHINGTON //  A US warplane shot down an Iran-made drone operated by pro-regime forces in southern Syria early on Tuesday, officials said, the second such incident in less than two weeks.

The US-led anti-ISIL coalition said an F-15E Strike Eagle jet destroyed the Shaheed-129 drone around 12.30am, north-east of the Al Tanaf garrison which is close to the Jordanian border.

"It displayed hostile intent and advanced on coalition forces," the coalition said.

Coalition troops were working in the area alongside local forces who are being trained to fight ISIL.

A US military official said the drone was "on a run toward our folks to drop a munition on them", so the coalition shot the unmanned aircraft down in self defence.

Al Tanaf, located on the key highway connecting Damascus with Baghdad, has been threatened by a surge of Iran-backed troops loyal to Syrian president Bashar Al Assad.

Coalition forces use the area - just north-east of the Jordanian border - as a training and staging area for attacks against ISIL.

The incident has similar hallmarks to a June 8 downing, when a US jet destroyed a pro-regime drone after it dropped what turned out to be a dud bomb near US-backed local forces.

It also comes after an American warplane shot down a Syrian government jet on Sunday in northern Syria as it "dropped bombs" near the Syrian Democratic Forces, a US-backed alliance fighting ISIL.

"Hostile intent and actions of pro-regime forces toward coalition and partner forces in Syria conducting legitimate counter-ISIS operations will not be tolerated," the coalition said.

The downing of the regime jet led Moscow to say it would sever a vital hotline it uses to communicate with the coalition to avoid mishaps in Syria's increasingly crowded and complicated battlespace.

Elsewhere on Tuesday, government air and artillery bombardments hit rebel-held areas of the Syrian city of Deraa, on the border with Jordan, after a two-day ceasefire expired, witnesses and the Syrian Observatory for Human Rights said.

It came as US and Russian officials held talks on creating a "de-escalation zone" in southwestern Syria that would include Deraa.

A witness and two rebels in Deraa said the Syrian army and its allies had resumed air and artillery bombardments in the city and the narrow strip of countryside separating it from the border.

If the army takes rebel-held parts of Deraa and the few kilometres between the city and the border, it would split the opposition areas of south-west Syria in half.

At least six raids took place in Gharz in east Deraa and in the old quarter of the city, where the army resumed efforts to break rebel lines, opposition fighters said.

The witness said that barrel bombs, artillery shells and rockets were used in the bombardment. Clashes took place near a military base south-west of the city near the border with Jordan, the witness added.

US and Russian officials agreed a ceasefire, which ended on Monday, during talks in Amman aimed at strengthening goodwill before more detailed negotiations on setting up the "de-escalation zone", diplomats in Jordan said.

On Saturday the Syrian army said it would suspend combat operations in Deraa for 48 hours in order to support "reconciliation efforts".

Rebels in the city and other residents have said this month that the army's bombardment of Deraa has intensified. Rebels said the government had brought more troops to the city.

Also on Tuesday, Russian deputy foreign minister Gennady Gatilov said Moscow could not confirm that ISIL leader Abu Bakr Al Baghdadi had been killed in an air strike in Syria last month, the Interfax news agency reported.

Russia said on Friday its forces may have killed the secretive ISIL leader, but Washington said it could not corroborate the death and western and Iraqi officials were sceptical.

Meanwhile, the World Health Organisation said at least 17 children had been paralysed by a polio outbreak in Syria since March, describing the situation as "very serious".

Fifteen more cases have now been confirmed since WHO first announced, less than two weeks ago, that Syria had been hit by its first outbreak of the crippling disease since 2014.

"We are very much worried, because if there is one case of polio with a kid that is paralysed, it is already an outbreak," said WHO spokesman Tarim Jasarevic.

He pointed out that for every polio-caused paralysis, there are on average nearly 200 children who have the virus but no symptoms.

"The virus is circulating. It is very serious."

The new cases all surfaced between March 3 and May 23, but were only just confirmed, since it can take up to two months to determine with certainty that a case of acute flaccid paralysis stems from polio, he said.

"It is expected that we will have more confirmations."

* Agence France-Presse and Reuters