At least 29 Afghan security force members died in Taliban attacks after air and ground assaults by government forces on the Islamist group.
The increase in hostilities signals a deadlock to stop-start peace talks involving US and Taliban negotiators in Doha.
The Defence Ministry said government forces killed 51 Taliban fighters in weekend assaults.
The Taliban hit back, attacking security checkpoints in Kunduz on Tuesday in which a security official said 15 Afghan army members were killed.
The Taliban also attacked a police station on Monday in Pul-e Khomri, capital of Baghlan province, killing 14 policemen, said Safdar Muhseni, head of the provincial council.
Taliban said it was responsible for both attacks. The group spokesman, Zabihullah Mujahid, said 35 Afghan security force members were killed in the attack in Kunduz and 17 in Baghlan.
Sources close to the Doha talks said the Taliban agreed internally to halt attacks against US forces and “reduce” assaults against Afghan government interests, but clashes increased.
Afghan forces and the Taliban clashed on Tuesday when security personnel tried to access a U.S. military plane crash site in central Afghanistan. US forces were later able to access the site and recover two bodies and what is believed to be the flight data recorder.