AL-QASR, LEBANON — Syrian soldiers backed by warplanes battled rebels for control of strategic hilltop villages near the Lebanese border on Friday, as government troops step up counterattacks against opposition forces threatening regime supply lines on the country’s frontiers.
Bomb blasts and shots fired into the air to mourn a fallen Syrian government soldier could be heard on the Lebanese side of the border as fighting raged around Qusair, a contested central Syrian town near a key highway between Damascus and the coast.
The battles there came as government forces launched a second offensive against rebels in the province of Daraa on the Jordanian border, where the opposition has been making steady advances in recent weeks.
While President Bashar Assad’s forces are stretched thin and much of the country has been allowed to slip into the hands of the rebels, the government is still fighting hard to keep control of airports, seaports, and roads linking them to the capital Damascus that are seen as essential to its survival.
Also on Friday, activists said rebels clashed with troops in the northeastern border city of Qamishli, 2 miles away from the border with Turkey. Fighting is rare in the predominantly Kurdish and Christian city, where rebels usually maintain a truce with the government.
It was not clear what prompted the clashes, which according to the Britain-based Syrian Observatory for Human Rights included members of the Islamist extremist Jabhat al-Nusra group.
Syria’s rebels have gained momentum and made significant gains in the past weeks, largely due to an influx of arms. Arab officials and Western military experts say Mideast powers opposed to Assad have stepped up weapons supplies to Syrian rebels, with Jordan opening up as a new route.
While much of the recent fighting has focused in Daraa, rebels have also made advances in Homs Province near Lebanon. The province saw some of the heaviest fighting during the first year of the Syrian conflict, which erupted in March 2011, and intermittent episodes of violence since.
On Friday, sporadic explosions inside Syria echoed across the Lebanese side of the border and an Associated Press reporter said Syrian warplanes carried out at least one airstrike inside Syrian territory near the town of Qusair.
Six people in the area, including two children, were killed when a shell struck their home, the Syrian Observatory for Human Rights said. Four rebel fighters were also killed.
The region overlooks a highway running between Damascus, Homs, and a coastal enclave that is the heartland of Syria’s Alawites, the minority Shi’ite offshoot sect to which Assad belongs, and is also home to the country’s two main seaports, Latakia and Tartus.
Overlooking Qusair from the Lebanese side are villages populated mostly by Shiite Muslim supporters of the Hezbollah militant group, which has backed Assad’s regime. The rebels are overwhelmingly Sunni Muslim.
Syrian TV reported Friday that armed forces ‘‘restored peace and security’’ to Tal al-Nabi Mindo, a village that it described as occupying the highest hill in the region. Activists say it was taken a month ago by rebels.
Members of the Popular Committees, a Hezbollah-backed group that has fighters in the border villages, said the Syrian army captured Tal al-Nabi Mindo on Thursday after a day of heavy fighting.