The Syrian army said its troops had abandoned Muhambal town and were regrouping for a counter-offensive

AMMAN, June 6 (Reuters) - Sunni Islamist groups have overrun Syrian army outposts and villages in western Idlib province, closing on coastal strongholds of President Bashar al Assad's government, rebels and a monitor said on Saturday.

The Syrian army said its troops had abandoned the town of Muhambal, which passes along a major highway from the city of Aleppo in the north to the coastal port city of Latakia and were regrouping for a counter-offensive. Social media videos showed army trucks and large caches of weaponry abandoned.

The Islamist alliance, including al Qaeda's Nusra Front, calls its operation the "Army of Fatah", a reference to conquests that spread Islam across the Middle East from the seventh century.

"After taking over several villages, we came from the mountains and entered the town and began combing it," said Abu Malek, a field commander from Nusra who led the advance against Muhambal, was quoted as saying on an opposition television station.

Syrian state television later said it killed "tens of terrorists" and destroyed large convoys carrying Nusra Front fighters in a series of air raids on their positions in Basankoul and a string of villages rebels had taken over.

WEAPONRY ABANDONED

The Syrian Observatory for Human Rights, which tracks violence across the country, said large caches of weapons were abandoned by the army when they fled the area.

Rebels have used American manufactured TOW anti-tank missiles against the Syrian army in weeks of heavy fighting, weapons that Damascus accuses Turkey and Saudi Arabia of supplying to insurgents seeking to topple Assad's government.

The main olive growing Idlib province is strategically located, bordering Turkey and adjoining Latakia, the coastal province on the Mediterranean whose mountains are the ancestral home of President Assad's minority Alawite sect.

The British-based Observatory said the Islamist insurgents intensified mortar shelling on army outposts in the strategic Jabal al Akrad mountain range that overlooks Alawite villages and close to Qardaha, hometown of the Assad family.

Nusra Front are rivals of the ultra hardline Sunni militants of Islamic State who also expanded their presence after taking control of the central city of Palmyra last month. It marked the first time the group had seized a Syrian city directly from government control.

(Reporting by Suleiman Al-Khalidi; editing by Ralph Boulton)

Our Standards: The Thomson Reuters Trust Principles.