Thousands of Syrians flee Daraa as regime shells ceasefire area

More than 12,000 people have fled their homes in southern Syria, as the regime bombards a ceasefire region in the country.

Opposition activists fear the intensive shelling could signal a long-awaited regime offensive on opposition Daraa province, which is held by the Free Syrian Army (FSA) and other rebel groups.

The recent bombardment started three days, the Syrian Observatory for Human Rights monitor said Thursday, with thousands fleeing the shelling.

The UN humanitarian coordination office reported that 2,500 people had fled one of these areas in the east of Daraa as of Wednesday. 

Syrian regime forces have been building up in the area ahead of an anticipated offensive. 

If pro-regime fighters attack opposition areas - and Russian plans joins the bombardment - then hundreds of thousands of civilians could be at risk.

Activists have reported that Bashar al-Assad's forces have prevented civilians fleeing bombarded areas by cutting roads.

Syrian rebel groups have reportedly joined under one command to defend the province.

The Syrian National Coalition has accused Assad of sending Iranian-backed Shia militias to take part in the planned offensive on Daraa and other opposition areas in the south.

"Neither the Russian nor the Iranian occupations will be able to break the will of the Syrian people or end their struggle against occupation and tyranny," said the coalition in a statement. 

"The Syrian people will eventually achieve their goals no matter the odds."

Daraa is covered by the so-called de-escalation zones, with the US warning any infringements of these ceasefire areas will be met with "firm and appropriate measures".

Israel has also been wary about the possible presence of Iranian-backed militias in the south and launched numerous air strikes on military positions in the area.

Agencies contributed to this story.