Taliban has made rapid headway in the northern areas in the past month Photograph:( AFP )
Taliban said its forces are closing in on Mazar-e-Sharif after a weekend blitz in which key provincial capitals fell to the militant groups.
US State Department said the situation in Afghanistan was "grave" and was rapidly deteriorating as the Taliban continued its sweep through the country.
"The increased tempo of Taliban military engagement, resulting in civilian causalities in armed conflict between the sides, and alleged human rights atrocities are of grave concern," US State Department said.
The Taliban has seized the sixth provincial capital. The group said its forces have been moving in on Mazar-e-Sharif.
The militant group has been on the offensive since mid-May and have escalated its fighting capabilities as President Biden announced last month that the last of the US troops will be out of Afghanistan by August 31.
"Ambassador Khalilzad will be in Doha to help formulate a joint international response to the rapidly deteriorating situation in Afghanistan," the US State Department said amid heavy fighting on the ground between Taliban and Afghan government forces.
The US has provided air support to the Afghan forces but it is unclear whether it will continue its bombing campaign beyond the end of this month.
"It's their country to defend. This is their struggle," Pentagon spokesman John Kirby said.
Meanwhile, the Taliban seized its sixth provincial capital after seizing districts in the rural areas in the north and south including key border crossing close to Tajikistan, Pakistan and Iran.
Kunduz, Sar-e-Pul and Taloqan have fallen to the Taliban with heavy fighting still continuing in Herat. The government forces have been pushed back in several areas as the Taliban has consolidated its gains engaging in street by street fighting in many cities.
Afghanistan's second-largest city Kunduz had fallen on Sunday as the Taliban continued its weekend blitz although the airport and army barracks were still being held by the Afghan forces.
The militant group is also engaged in heavy fighting in Kandahar and Lashkar Gah with the conflict going on for the past several weeks.
(With inputs from Agencies)