Taliban militants captured a district near the northern Afghan city of Kunduz on May 6, officials said.
Mahfouz Akbari, a police spokesman for eastern Afghanistan, said security forces had pulled out of Qala-i-Zal district, west of Kunduz city, on May 6 after more than 24 hours of heavy fighting.
In a statement, Taliban spokesman Zabihullah Mujahid said the insurgents had taken police headquarters, the governor's compound, and all security checkpoints. He said several police officers and soldiers had been killed and wounded.
Over the past 18 months, Taliban fighters have twice succeeded in seizing the town center of Kunduz for brief periods.
In a separate incident, at least four police officers have been shot to death in Afghanistan's southern Helmand Province, according to a police official.
General Aqa Noor Kentoz, provincial police chief, said on May 6 that all four had been killed the night before at a checkpoint on the outskirts of the provincial capital, Lashkar Gah.
Kentoz says the four might have been attacked by an insider. An investigation is under way, he said.
No one immediately claimed responsibility.
According to U.S. estimates, government troops control only some 60 percent of the country, with the rest either controlled or contested by the insurgents, who are seeking to reimpose Islamic law after their 2001 ouster.
More than 1,000 members of Afghanistan's security forces have been killed since the start of the year, according to Afghan officials and figures cited by U.S. congressional watchdog SIGAR, along with over 700 civilians.
According to the United Nations, some 75,000 people have also been forced to flee their homes in the first four months of the year.
Earlier this year, the top NATO commander in Afghanistan, General John Nicholson, said a few thousand more international troops are needed to boost the Resolute Support training and advisory mission and break a "stalemate" with the Taliban.