Syrian regime jets bomb rebel positions near Jordan border

Syrian regime forces and US-backed rebel fighters clashed in a remote desert area near the Jordanian border early on Tuesday, opposition groups have said.

"The Syrian regime's jets conducted four strikes against us," said Tlas al-Salameh, the commander of Osoud al-Sharqiya ["Eastern Lions"], a Western-backed Free Syrian Army (FSA) faction which is the largest operating in the Syrian Desert bordering Jordan.

According to Salameh, one air strike hit a border area where the rebel group shelters families of its fighters.

Others hit a rebel outpost eight kilometres from the Rukban camp, where more than 80,000 refugees are stranded on the Syrian-Jordanian border.

The group suffered no casualties in the air strike, Salameh said, accusing government troops of "obstructing" his group's efforts against Islamic State group militants.

"The regime forces have entered the area and blocked the way between us and Daesh," Salameh said, using an Arabic acronym to refer to IS. "We can't get to Daesh."

He said clashes were concentrated on the highway linking the Syrian capital, Damascus, with Baghdad, mostly at the Zaza junction, a triangle on the highway that leads to Homs, Damascus, and Iraq.

Salameh added that rebels responded by striking at Khalkhala airbase and a regime-controlled power station nearby.

The clashes came one day after Syrian media said the US, UK and Jordanian forces were "massing" on the Jordanian side of the border. The report was likely a reference to an annual US-Jordanian military drill known as "Eager Lion".

Jordan's state-run Petra news agency said about 7,400 troops from more than 20 nations were participating.

On Monday, Syria's Foreign Minister Walid al-Muallem warned Jordan against sending troops to Syria, adding that the government troops' next target would likely be to reach the border with Iraq.

The UK-based Syrian Observatory for Human Rights said Tuesday's clashes were underway on the southern edge of Syria's central Homs province, where government forces have been on the offensive for days.

Both Syrian regime troops and opposition fighters are battling the Islamic State group, which declared a so-called caliphate in 2014 in areas it seized in Syria and Iraq. Since then, IS has lost wide areas after coming under attack in Syria and Iraq from a US-led international coalition.