Chief Syrian opposition peace talk negotiator resigns

Alloush, from the High Negotiations Committee (HNC), said the talks had not brought a political deal or eased the plight of Syrians in besieged areas.

The HNC suspended its involvement in the UN-brokered "proximity" negotiations with a Syrian government delegation in Geneva in April over intensifying of regime air strikes in recent weeks.

The UN-backed parties have not set a date for the resumption of the peace talks.

Meanwhile, Syrian rebels have taken two villages from the Islamic State of Iraq and the Levant (ISIL) as they fought to undo gains made by the group in a surprise offensive days earlier, activists have said.

"The three rounds of talks were unsuccessful because of the stubbornness of the regime and its continued bombardments and aggressions against the Syrian people," Alloush said.

The Saudi-backed HNC has for months expressed its frustration about the progress of the Geneva talks.

According to the BBC, the group has been angered by the lack of humanitarian aid reaching besieged areas, the slow release of political detainees and the absence of movement towards a political transition in Syria without President Bashar al-Assad.

A nationwide truce brokered by the US and Russia between rebel and government forces is officially still in place, but is frequently violated.

Meanwhile, Syrian rebels have taken two villages from the Daesh as they fought to undo gains made by the group in a surprise offensive days earlier, Aljazeera reports.

Alloush's resignation could prompt further departures. The BBC states that reports of another member of the HNC show signals that he may resign also.