BEIRUT (Reuters) - Heavy clashes between Syria's army and insurgents erupted around a military base south of Idlib city on Monday as part of a wider battle for control of the northwestern province, Syrian state television and a group monitoring the war said.
The Mastouma base is one of the last major army strongholds in a province controlled by a range of insurgent groups including al Qaeda's Syrian wing, the Nusra Front, and the Islamist Ahrar al-Sham movement, fighting to overthrow President Bashar al-Assad.
Army units "inflicted great losses" on armed groups in battles to the north and around Mastouma, Syrian state television reported, citing a military source.
The British-based Syrian Observatory for Human Rights said most of the troops positioned in Idlib city were now in Mastouma after insurgents took over the provincial capital in March. The base is used for launching air raids in the province.
There were reports of casualties in the battles, it said, without giving details. The Syrian air force also bombarded the area in a series of raids, it added.
Syrian state television reported clashes around Filoun village to the west of the base, which is located on a major road heading south out of Idlib city.
The base is east of the town of Jisr al-Shughour, which was captured by the Sunni Islamist insurgents in April, an advance that brought them closer to the coastal areas that form the heartland of the minority Alawite sect to which Assad belongs.
It has been one of the toughest periods for Assad since the first two years of the conflict which spiraled out of protests against his rule, part of the wider 2011 Arab uprisings against autocratic leaders.
In the last week, Iranian-backed Hezbollah has started a major campaign to drive insurgents from large areas of the Qalamoun mountain range along the border with Lebanon, a short drive from the capital Damascus.
Lebanon's Hezbollah-run al-Manar television said on Monday that 10 militants had been killed and 20 wounded when the army and Hezbollah fighters attacked them in the Qalamoun area and the town of Fleita.
The channel broadcast footage filmed from an armored vehicle and from the air showing fighting in the Qalamoun area. Hezbollah fighters were shown firing weapons with munitions that kicked up clouds of dust from the ground on impact.
Hezbollah and the Syrian army made big advances against insurgents in the mountains north of Damascus last week, shoring up Assad's grip on the border zone.
(Reporting by Sylvia Westall; Editing by Dominic Evans)