REBELS AIM TO SEIZE DERAA

The United States has rejected the idea of working with Assad in the war against Islamic State.

Elsewhere in Syria, Assad's government has faced increased military pressure since March, losing ground in the northwest, the south and the centre of the country, where Islamic State seized the city of Palmyra from government control last month.

The rebels in the south launched their assault on Thursday to capture Deraa, which, if it falls, would be the third provincial capital lost by Assad in the four-year-long war, after Islamic State-held Raqqa and Idlib held by another rebel alliance.

Assad's control is now mainly confined to the major population centres of western Syria, where he has sought to shore up his grip with the help of Lebanon's Hezbollah Shi'ite militia, his main allies.

An alliance of rebel groups known as "The Southern Front", which profess a secular vision for Syria, said its Deraa offensive had begun at dawn. The al Qaeda-linked Nusra Front also has a presence in the south.

"If the battle takes time, we are prepared. We have begun the preparatory shelling but we cannot assess the situation right now," Issam al-Rayyes, spokesman for the so called Southern Front, said.

Deraa's provincial governor Khaled al-Hanous told state TV the insurgents had launched "a real war with intensified shelling with various weapons or artillery on citizens in the neighbourhoods of the city and on hospitals, schools and infrastructure".

The rebels had not made "one metre of progress", he said.

The Observatory reported heavy fighting and army air strikes in the Deraa area.