Scores of Syrian rebels and forces loyal to President Bashar al-Assad were killed in fierce fighting Wednesday south of Damascus, where the army pressed a major offensive, an NGO said.
The fighting, between rebel brigades and regular troops, supported by militia and elements of the Lebanese Shiite movement Hezbollah, took place in the areas of Husseiniyah, Al-Thiyabiyeh and Bouaydah, as government warplanes pounded the area, the Syrian Observatory for Human Rights said.
"At least 22 people, the majority of them rebels, including a commander," were killed, the Britain-based group said, without elaborating.
At the same time, it said "dozens" of regime forces were killed.
Earlier, the Observatory had said regular troops had reinforced their control of two villages separating Thiyabiyeh and Bouaydah.
For its part, the Local Coordination Committees, a group of militants on the ground, said the Abu Fadel Abbas Brigade composed mostly of Iraqi Shiites, along with Hezbollah fighters and elite troops were carrying out a major offensive.
State news agency SANA said government forces had "tightened their control over the town of Husseiniyah and the outskirts of Al-Thiyabiyeh."
The two towns are located near the Shiite pilgrimage site of Sayyida Zeinab in the southern outkirts of Damascus.
Clashes has been reported in the area for months and fighters from Hezbollah, which backs Assad's regime, have been dispatched to protect the site.
Separately, rebels seized a guard post on the Jordanian border after a month of fierce fighting, the Observatory said.
"Rebel fighters took control of the Hajanah border battalion post near the city of Daraa after laying siege to it for two months and fierce clashes around it lasting a month," the NGO said.
Some of the border guard battalion had withdrawn, and there was no immediate word on any casualties during the post's capture.
The border post is adjacent to an old customs post seized by rebels days earlier.
With its capture, opposition forces now control a ribbon of territory along the border from outside Daraa to the edge of the Israeli-occupied Golan Heights.
In the northern city of Aleppo, the Observatory reported fighting in the Salaheddin neighbourhood, where opposition rebels were advancing.
Clashes killed 10 troops, and deaths were reported among the rebels as well, the group said.
In the central city of Homs, rebel shelling of one of Syria's two main oil refineries set fire to the plant, already working at barely 10 percent of its capacity, the Observatory said.