An Afghan helicopter carrying security personnel arrives at the scene of an operation against Taliban insurgents in Kunduz on September 30, 2015
Kunduz (Afghanistan) (AFP) - NATO said Wednesday its special forces joined Afghan troops in Kunduz to try to push back Taliban insurgents who seized the city, repelled a counter-offensive and advanced on the airport to shore up their biggest victory in 14 years.
Heavy fighting was underway near the northern city's airport, where government forces are holed up, highlighting the potent challenge the militants pose after their lightning capture of Kunduz.
The Taliban also captured the military hilltop of Bala Hisar Wednesday, tightening their grip on Kunduz and leaving all but the airport under the control of Afghan forces.
The Taliban's occupation -- now in its third day -- raises troubling questions about the capabilities of Afghan forces as they battle the militants largely on their own after NATO's combat mission ended last December.
The Afghan army was supposed to be bolstered by its own reinforcements for the campaign to retake Kunduz, but Taliban ambushes on convoys headed for the city meant that back-up troops were only trickling in.
"The Taliban have laid landmines and booby traps around Kunduz, slowing the movement of convoys of Afghan army reinforcements driving to the city," an Afghan security official told AFP.
NATO said the foreign special forces had reached Kunduz and US forces had conducted three air strikes around the city since Tuesday to support the Afghan troops.
The forces are comprised of US, British and German troops, a Western military source told AFP on condition of anonymity, without specifying the number.
But a government spokesman in Berlin said the German troops who reached Kunduz on Tuesday left the city on the same day.
The fall of the provincial capital, which sent thousands of panicked residents fleeing, has dealt a major blow to the Afghan military and highlighted the insurgency's potential to expand beyond its rural strongholds.
The Afghan security official said the militants had slowly infiltrated Kunduz during the recent Eid festival, launching a Trojan horse attack that enabled them to capture it within hours.
Pentagon press secretary Peter Cook said the fall of the city on Monday -- achieved by a militant force significantly smaller than the army contingent -- was "obviously" a setback but the US believed Afghan authorities would be able to regain control.
Cook added he was "not sure it reflects any new assessment of the Taliban", but several analysts see it as a game-changer for a group that many had believed was fraying.
- 'Ghost town' -
Despite the military build up, Kunduz remained largely under Taliban control -- the first major urban centre in their grasp since they were toppled from national power in 2001.
Fighters erected checkpoints across the city and were seen racing stolen police, UN and Red Cross vehicles.
Local bakeries were selling stale bread at inflated prices and residents reported woeful shortages of water, medicines and electricity, as many people hunkered down in their homes amid frequent gunfire.
"Kunduz looks like a ghost town. Only a few dare to go out -- every few minutes you hear gunshots," a local doctor, who did not want to be named, told AFP.
"The Taliban this morning used loudspeakers, telling people to reopen shops, but who would dare do that?"
Insurgents, showing off seized tanks and armoured cars, have issued edicts against looting and vowed to enforce Islamic sharia law.
Rights groups say the Taliban have exposed civilians to grave danger by hiding in people's houses and conducting door-to-door searches for Afghan security personnel or government staff.
In a televised speech on Tuesday Afghan President Ashraf Ghani said the Taliban were using civilians as human shields, hampering the counter-offensive since troops were trying to prevent casualties.
Precise losses in the fighting were not known, but the Afghan health ministry said hospitals in Kunduz had so far received 43 bodies and more than 330 wounded.
The United Nations said the fighting has forced up to 6,000 civilians to flee the city.
- Expanding insurgency -
The Taliban's recent gains in Kunduz and neighbouring provinces highlight that a large and strategic patch of northern Afghanistan is imperilled by a rapidly expanding insurgency.
"If air strikes increase, we might have to retreat tactically from Kunduz, but we plan to expand the war towards neighbouring Takhar and Balkh provinces," a senior Taliban source based in northwestern Pakistan told AFP.
Kunduz province, which borders Tajikistan and is a major transport hub for the north of the country, could offer the Taliban an important new base of operations.
The fall of the city coincided with the first anniversary of Ghani's national unity government.
It has renewed questions about Washington's plan to withdraw most US troops from Afghanistan next year.
Even after years of training and equipment purchases -- on which Washington spent a whopping $65 billion -- Afghan forces have been unable to rein in the ascendant insurgency.
"Despite their many improvements in recent years, (Afghan forces) remain a work in progress," said Michael Kugelman, Afghanistan expert at the Washington-based Woodrow Wilson International Center for Scholars.
"And given the extent of the Taliban threat, work in progress isn't good enough."