KANDAHAR: Afghan forces clashed on Friday with Taliban fighters in an operation to retake a key border crossing with Pakistan, as the insurgents tightened their grip in the north and battled for the stronghold of an infamous warlord.

The fighting at Spin Boldak follows weeks of intensifying clashes across Afghanistan, with the Taliban capitalising on the last stages of the US troop withdrawal to launch a series of lightning offensives, overrunning districts at a staggering rate.

The group have also taken other vital border crossings in the north and west.

A senior official on the Pakistan side of the frontier said heavy fighting could still be heard late Friday afternoon, and noted the Taliban’s white flags remained flying over the crossing.

Following fierce skirmishes overnight, dozens of wounded Taliban fighters were brought across the border, an eyewitness at the scene reported.

“We have suffered one death and dozens of our fighters have got injured,” Mullah Mohammad Hassan, who identified himself as a Taliban insurgent, said near Chaman, about five kilometres from the border.

The Spin Boldak-Chaman border crossing is an economic lifeline for southern Afghanistan.

The landlocked country depends on the crucial commercial artery to export much of its agricultural produce, such as almonds and dried fruits, while also serving as the entry point for finished goods coming from Pakistan.

Controlling the crossing will likely provide the Taliban with an economic windfall, allowing the insurgents to tax the thousands of vehicles that pass through the frontier daily.

The border was closed as of late Friday afternoon, with nearly 2,000 people massed near its gate on the Pakistan side.