Helicopter gunships hover in the sky and the night air crackles with the sound of gunfire, but rebel fighters encircling the key Wadi Deif military base in northwestern Syria stand their ground.
"We have been besieging Wadi Deif for a week and will not back down even if they bombard us with barrels of TNT and cluster bombs," says Abdelkader, a rebel commander.
"We are holding out well and soon, you'll see, we will seize Wadi Deif," he says.
The besieging force -- rebels of the Free Syrian Army, backed by groups of Islamist militants -- are armed with little more than assault rifles and Soviet-era Dushka heavy machine guns mounted on four-wheel drive vehicles.
But since they captured the strategic town of Maaret al-Numan along the Aleppo-Damascus highway on October 9, they have prevented troop reinforcements from getting near the military base -- or, more importantly, further north to the key battleground city of Aleppo.
Syria's military is relying on air power to dislodge the rebels and early Thursday warplanes launched a new wave of strikes on Maaret al-Numan and its surrounds.
But despite the best efforts of the air force, some 250 soldiers remain trapped inside Wadi Deif base, a key storage facility for fuel and weapons about two kilometres (1.25 miles) from Maaret al-Numan.
Rebel snipers equipped with semi-automatic Dragunov rifles relentlessly pepper the base with gunfire, lurking behind sandbags that buttress the windows and walls of abandoned villas they have claimed as their frontlines.
"BMP," shouts a fighter who has just spotted a Soviet-era infantry vehicle moving in the distance.
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A sniper aims, fires and reloads, ready for the next target.
"We don't need any help," says rebel commander Abdelkader.
"God is on our side and we will win (this battle) and push the fight all the way to Damascus," he adds.
The rebels are trying to establish a "safe" zone in north Syria along the Turkish border, where they already control vast swathes of countryside and towns and villages, even as the battle for the commercial capital Aleppo rages into a fourth month.
The capture of Maaret al-Numan marked an important turning point as it halted efforts by the military to reinforce positions at Aleppo and allowed the rebels to consolidate their gains.
On Tuesday a convoy of military vehicles tried to make its way along the highway but was stopped by the rebels who destroyed four army tanks and forced the rest of the convoy to withdraw further south, insurgents say.
The rebels were buoyed further on Wednesday when they shot down a regime helicopter gunship that dared fly too close to their positions.
The aircraft was hit by a round of heavy machinegun fire and exploded in mid-air before crashing near Maarhtat, on the outskirts of Maaret al-Numan, videos posted by activists on YouTube show.
One video shows the helicopter spiralling out of the sky and then exploding, as onlookers cry out: "Allahu akbar! (God is greater)."
The authenticity of the videos could not immediately be verified.