ALEPPO (Reuters) - Forces loyal to President Bashar al-Assad, backed by a dawn barrage of artillery fire and air strikes, drove Syrian rebels from a strategic military base near the disputed northern city of Aleppo on Friday, a local photographer said.
The advance into Base 80, a large military position which rebels have held since February, will help Assad's forces move towards rebel-held areas of Aleppo city and follows a string of successful offensives this month.
But the fight continued on Friday afternoon after rebels regrouped and clashed with the army at the base, activists said. Opposition video footage showed rebels firing heavy machine guns.
Once Syria's most populous city, the former commercial hub of Aleppo has been divided roughly in half by the warring parties. Rebels hold most of Aleppo province but the government wants to keep a foothold in the north, where rebel supplies flood in from Turkey.
A photographer who supplies pictures to Reuters arrived at the scene about 1 km (0.6 miles) from Base 80 at dawn and said he saw around two dozen air strikes and artillery hitting insurgent positions.
Rebels from Liwa al-Tawid, the largest insurgent force in Aleppo, told him that their unit as well as dozens of others had been pushed out of most parts of the base, next to Aleppo International Airport, which is still under government control.
Rebels told him 25 of their fighters had died.
A monitoring group that uses a network of pro- and anti-Assad sources said that the offensive was aided by the Lebanese Shi'ite militant group Hezbollah and pro-Assad militia.
The group, the Syrian Observatory for Human Rights, said that hardline Islamist rebel units linked to al Qaeda also took part in the clashes, which it said killed at least 23 rebels and several pro-Assad militants.
State media did not mention the offensive.
The armed forces captured the town of Safira, 20 km (12 miles) south-east of Aleppo, a week ago.
The army said at the time that Safira would be used to send in medicine and supplies to government-controlled areas of Aleppo, mired in a bloody stalemate for over a year. Its capture would have helped Friday's attack on Base 80, on the southeastern fringes of the city.
Assad's forces also took the strategic southern town of Sbeineh near Damascus on Thursday, threatening rebel control of the wider area and cutting off a supply route for insurgents around the capital.
After 2-1/2 years of war, which started when Assad's forces fired on pro-democracy protests, the fighting has settled into a broad stalemate in which more than 100 are killed every day.
More than 100,000 have died since the start of the conflict, the United Nations says, and millions more are displaced.
(Reporting by Molhem Barakat; Writing by Oliver Holmes in Beirut; Editing by Mark Trevelyan)