A Taliban attack on an army outpost near the northern city of Kunduz in Afghanistan has killed at least 29 soldiers.
Meanwhile, air strikes in other parts of the country killed dozens of insurgents, reports Reuters quoting Afghan officials.
On the day that NATO leaders meeting in Brussels were discussing Afghanistan, the fighting was a sharp reminder that no end to the war is in sight despite the hundreds of billions of dollars spent by Kabul’s international allies.
Kunduz, a strategic northern city which the Taliban have come close to taking twice in the past three years, has been relatively calm but fighting has picked up since the end of a three-day truce during last month’s Eid al-Fitr holiday.
Sunnatullah Temori, a spokesman for the governor in neighbouring Takhar province, said the soldiers were killed when the Taliban stormed a base in Pul-e-Momin, an area between the provinces of Kunduz and Takhar late on Wednesday.
He said the insurgents had seized a large quantity of weapons and ammunition and said fighting was threatening the centre of nearby Khwaja-e-Ghar district, which he warned could fall if reinforcements were not sent quickly.
The latest fighting comes despite speculation about possible peace talks between the government and the Taliban, with calls from a special religious council meeting in Saudi Arabia this week for negotiations to end the 17-year conflict.
The United States last year stepped up air strikes as part of a strategy to force the Taliban to the negotiating table and commanders say that together with the fledgling Afghan air force, the campaign has inflicted heavy casualties on the insurgents.
However, despite the temporary Eid ceasefire, the Taliban have rejected peace talks while Islamic State militants, opposed to both the Western-backed government and the Taliban, have claimed a series of deadly suicide attacks in the past two weeks.
On Thursday, officials said dozens of militant fighters were killed in ground and air operations in Zurmat and Ahmad Aba districts of the eastern province of Paktia while in Ghazni, to the south, at least 27 Taliban were killed by an air strike on Wednesday.
Heavy fighting was also reported in the western province of Farah, where the Taliban came close to overrunning the provincial capital in May.
In Logar province, immediately to the south of Kabul, the Taliban burned down a school, the second they have destroyed in a month, Kabir Haqmal, a spokesman for the ministry of education said.