The Taliban seized a sixth Afghan provincial capital on Monday following a weekend blitz across the north that saw urban centers fall in quick succession and the government struggle to keep the militants at bay. 

Insurgents entered Aybak without a fight after community elders pleaded with officials to spare the city from more violence following weeks of clashes on the outskirts, said Sefatullah Samangani, deputy governor of Samangan Province.   

"The governor accepted and withdrew all the forces from the city," Samangani added, saying the Taliban were now in "full control." 

A Taliban spokesman confirmed the city had been taken. 

The Afghan Interior Ministry said earlier on Monday that government forces had repelled a Taliban attack on Aybak on Sunday night, killing at least 20 militants and wounding eight others.

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Fighting in Afghanistan's long-running conflict has intensified since May, when foreign forces began the final stage of a withdrawal due to be completed later this month.   

Many Afghan cities and about half of the country's 34 provinces have been the scene of heavy battles and street fighting in recent weeks as Taliban militants continued their fighting against security forces. The insurgents have snatched up six provincial capitals since Friday, including Zaranj, Shaburhan, Kunduz, Sari Pul, Taluqan and Aybak. 

Afghan commandoes launched a counter-attack on Monday to try to beat back Taliban fighters who overran the northern city of Kunduz a day earlier.

A spokesman for the Taliban's political office told Al-Jazeera TV on Sunday that there is no agreement on a ceasefire with the Afghan government, and warned against further U.S. intervention in Afghanistan. 

Ryan Crocker, former U.S. ambassador to Afghanistan, said on Sunday that a prolonged civil war in Afghanistan is more likely than a rapid Taliban takeover. 

"A prolonged civil war is a more likely outcome than a swift Taliban takeover of the entire country. They're being very smart about this. They're not launching major strikes into Kabul," Crocker told ABC's This Week.

Zalmay Khalilzad, special U.S. envoy on Afghanistan, said last week that the Taliban and the Afghan government are far apart in their talks on bringing peace to the country, with the former demanding "the lion's share of power" in a new government and Kabul wanting to bring them into the current government. 

During a recent visit to China, the Taliban's political chief Mullah Abdul Ghani Baradar said the group is sincere about seeking peace and is willing to work with other parties to create an extensive and inclusive political arrangement that is acceptable to all Afghan people. 

(With input from agencies)

(Cover: Smoke rises from damaged shops after fighting between the Taliban and Afghan security forces in Kunduz, northern Afghanistan, August 8, 2021. /CFP)