The US military is closely watching the security situation in Afghanistan after new gains were made by the Taliban against government forces during the gradual withdrawal of American troops, officials said on Wednesday.
Gen Mark Milley, chairman of the Joint Chiefs of Staff, told Congress that 81 of the 419 district centres were now under Taliban control.
The Taliban say they have taken possession of dozens of districts in the past two months alone, although Gen Milley said 60 of those had been captured last year before the US began its final withdrawal.
He said the Taliban had not captured a single provincial capital.
However, Taliban fighters took control of an important district in Afghanistan’s northern Kunduz province on Monday and encircled the provincial capital, Afghan police said.
In the same hearing, Defence Secretary Lloyd Austin made clear the Taliban's gains were not interfering with the final withdrawal of US troops, ending nearly two decades of war.
As the withdrawal is now more than half complete, the US appears to be on track to reach a full departure by the September 11 deadline.
"We are focused and the task that we have at hand is to conduct our retrograde in a safe, orderly and responsible fashion," Mr Austin told the panel.
"We've developed a very detailed plan to do that. And we have accomplished the task according to plan thus far, and really provided for the safety of not only our forces but our allies as well."