BEIRUT -- Syrian rebels stepped up their siege of a government helicopter base and clashed with soldiers near Aleppo's international airport Friday, part of an effort to chip away at the air power that poses the biggest challenge to their advances against the regime of President Bashar Assad.
That airborne threat asserted itself the same day when a government airstrike on a northern town killed 14 people, mostly women and children, activists said. More than 21 months into the Syrian civil war, the Assad regime is counting more than ever on its air force to block rebel gains.
Rebels in the north, a region largely clear of government troops, realize this and have launched campaigns to seize all the area's airports, hoping it will protect their forces and the civilians who back them.
Rebels say they have surrounded four airports in the northern province of Aleppo. In recent days, they have posted dozens of videos online showing fighters shooting mortars, homemade rockets and sniper rifles at targets inside the bases.
It remains unclear whether rebels can seize any of the bases soon, but they have managed to stop air traffic at one and limit movement at others by firing on all approaching aircraft with heavy machine-guns.
"The airports are now considered the most important thing the rebels can focus on, because all of the strikes now come from the air," Aleppo activist Mohammed Saeed said via Skype.
Saeed said clashes between rebels and government soldiers raged until Friday morning around the Mannagh helicopter base near the Turkish border. He said other rebel groups continued to hold positions around the Kuwiras military airport southwest of Aleppo and clashed with soldiers near the city's international airport and neighbouring Nerab military airport.
Rebels have numerical superiority and support from most of the population in the far north, making it easy for them to surround and cut off ground supply lines to government military bases.
But Assad's forces still control the air, responding to rebel gains with airstrikes on their positions or residential areas, a tactic rebels consider collective punishment against civilians backing the revolt.
On Friday, Russian Foreign Minister Sergey Lavrov told reporters Russia has contacted the Syrian National Coalition for Opposition and Revolutionary Forces through the Russian Embassy in Egypt to suggest a meeting with coalition leader Mouaz al-Khatib.
In an interview with Al-Jazeera TV, al-Khatib criticized the offer and said Assad's ouster is "a main condition in any negotiations."
-- The Associated Press