The Afghanistan government replaced its army chief, as Taliban militants continue to make rapid advances.
The insurgents have now taken control of at least nine of the country’s 34 provincial capitals.
Heavy fighting was reported on Wednesday in the cities of Kandahar and Ghazni.
President Ashraf Ghani earlier flew to the northern city of Mazar-i-Sharif – traditionally an anti-Taliban bastion – to try to rally pro-government forces.
General Wali Mohammad Ahmadzai had only been in the post since June.
His successor will have to deal with escalating violence across the country, as the Taliban continue their offensive. US and other foreign troops have all but withdrawn following 20 years of military operations.
More than 1,000 civilians have beeAn killed in Afghanistan in the past month, according to the UN.
On Wednesday, President Ghani held crisis talks in Mazar-i-Sharif with ethnic Uzbek warlord Abdul Rashid Dostum and prominent ethnic Tajik leader Atta Mohammad Noor about defending the city.
Mr Dostum, a veteran commander, was quoted as saying: “The Taliban have come to the north several times but they were always trapped.”
For years, Mr Ghani tried to sideline the warlords in an attempt to boost the Afghan National Army, and now he is turning to them in his hour of need.
Earlier this week, the president also agreed to arm pro-government militia.
Mazar-i-Sharif lies close to the borders with Uzbekistan and Tajikistan, and its loss would mark the complete collapse of the government’s control over the north of Afghanistan.
In Kunduz, another northern provincial capital, hundreds of government soldiers who had earlier retreated to the airport after the Taliban overran the city have now surrendered.
Reports claim in eastern Afghanistan’s Ghazni Taliban insurgents entered the city centre.
The International Committee of the Red Cross (ICRC) humanitarian group later said intense “street-by-street” fighting was taking place in Afghanistan’s second-largest city Kandahar.
The Taliban claimed to have taken over the city’s prison, something that the government is yet to confirm.
In the city of Lashkar Gah, in Helmand province, ICRC director-general Robert Mardini said hospitals were “struggling to deal with the dead bodies”.
In addition to fighting on the ground, US and Afghan planes have been carrying out air strikes against Taliban positions in the country.
With violence surging, thousands of people have been fleeing in search of safety.