The top US commander in Afghanistan Tuesday did not rule out conducting air strikes against the Taliban if they pressed on with their campaign of capturing new territory across the violence-wracked country.

Fighting has surged across the rugged countryside since early May when the US military began its final withdrawal of troops, with the Taliban claiming to have recently captured more than 100 of the over 400 districts across Afghanistan.

"What I like to see is no air strikes, but to get to no air strikes, you stop all violence," General Scott Miller told reporters in Kabul on Tuesday, according to video footage obtained by AFP from US-funded Radio Free Europe/Radio Liberty.

"The best way to stop those, and I have actually told the Taliban this, is stop the offensive operations and air strikes," he said, insisting that the US military still has the fire power to conduct air strikes against the insurgents even as it continues the withdrawal.

The remaining US troops are expected to be out by the September 11 deadline announced by President Joe Biden to end America's longest war.

The Taliban's claims of capturing districts are often disputed by government officials and are difficult to independently verify.

But experts say one of the main reasons the Taliban has been able to capture scores of new districts in recent weeks is the lack of US air support to Afghan ground forces fighting across rural terrains.

Miller, who is soon to transition to another commander, acknowledged that any loss of territory has an impact on the overall security in the country.

"Because districts start representing key terrain as it relates to security of the people, of the provincial capitals and certainly security of the capital," he said.

The Taliban recently captured a key border crossing with Tajikistan in the north along with other districts surrounding the city of Kunduz, effectively laying a siege to the city.

The insurgents have also encircled almost all major cities in the country, raising fears that they would also make a military push to capture Kabul after the US and NATO forces leave.

"A military takeover is not in the interest of anyone, certainly not for the people of Afghanistan," Miller said, adding that the overall security situation was "not good".

"That's something that's recognised by the Afghan security forces and they are making the appropriate adjustments as we move forward," he said.

Faced with the Taliban's blistering assault, Afghan interior ministry said Tuesday it has created a 4,000 member "rapid reaction force" to be led by retired army generals who would fight the Taliban along with regular security forces.