Syrian forces have battled rebels in the central province of Homs near the border with Lebanon as part of a counter-offensive aimed at regaining control of territory around the country and along strategic border areas.
With a fresh influx of weapons, opposition fighters have made significant gains in the past weeks, particularly in the southern province of Daraa, where rebels have been advancing in the region between the Jordanian border and the capital, Damascus.
The province of Homs and its capital of the same name were the scenes of some of the heaviest fighting during the first year of Syrian conflict. The violence has escalated there in recent weeks, with Syrian war planes hitting the city daily. On Friday troops clashed with rebels on the edges of the province along the Lebanese border.
The border area is strategically important to both sides fighting in Syria's civil war and battles there have been frequent in past weeks, particularly in and around the town of Qusair in Homs province.
The area is considered vital to the Syrian regime because of its location along a road linking Damascus with the city of Homs, a strategic supply route for the military. The rebels also have been using the road to transport supplies and weapons from Sunni supporters in Lebanon.
The Britain-based Syrian Observatory for Human Rights said the clashes between soldiers and opposition fighters were concentrated around Qusair. There were no immediate reports of casualties.
Overlooking Qusair from the Lebanese side are villages populated mostly by Shiite Muslim supporters of the Hezbollah militant group, who have supported President Bashar Assad's regime during Syria's two-year conflict.
The rebels fighting to topple Assad, a member of the minority Alawite sect, are overwhelmingly Sunni Muslim. The Alawites are an offshoot of Shiite Islam. The conflict started with largely peaceful protests against Assad's regime in March 2011 but eventually turned into a civil war that has increasingly taken sectarian overtones. More than 70,000 people have been killed in the war, according to the United Nations.
Also today, Syrian warplanes carried out airstrikes around the country, hitting targets in Daraa in the south, in Hasaka province in the north east near the border with Turkey and in the northern city of Aleppo, parts of which have been under rebel control since last summer.
The airstrikes come a day after a US-based human right group accused the Syrian air force of carrying out indiscriminate attacks on civilian areas around the country - attacks the group claims amount to war crimes. More than 4,300 people have been killed in aerial bombardments since last summer, Human Rights Watch said in a report on Thursday.