Security forces had pulled out of the Qala-i-Zal district, west of Kunduz city, on Saturday to avoid further civilian and military casualties following 24 hours of heavy fighting, Mahfoozullah Akbari, police spokesman for eastern Afghanistan said.

Taliban militants attacked the district "from several directions on Friday afternoon, and took control of the district fully by mid-morning on Saturday," Akbari said, adding that security forces had to abandon the police headquarters and the other government institutions as security reinforcements failed to arrive in time.

Spring offensive

In a statement, Taliban spokesman Zabihullah Mujahid said the militants had killed scores of members of Afghanistan's security forces and had captured a large amount of weapons during the operation.

He also confirmed that the insurgents had taken control of police headquarters, the governor's compound, and all security checkpoints and that several police and soldiers had been killed and wounded in the assault.

Over the past 18 months, Taliban insurgents have twice succeeded in seizing the nearby town center of Kunduz for brief periods. The group has vowed to ramp up operations against Afghan and foreign forces throughout the country. According to US estimates, government fighters control only around 60 percent of the country, with the rest either controlled or contested by various Islamist insurgents. The latest fighting hints at another year of fighting in store for Afghan forces.

More than 1,000 members of Afghanistan's security forces have been killed in clashes with insurgents since the start of the year, according to officials, alongside over 700 civilians.

Some 75,000 people have also reportedly been forced to flee their homes in the first four months of the year, according to the United Nations.

Attack in Helmand province

The Associated Press news agency, meanwhile, reported that at least four police officers were killed in Afghanistan's southern Helmand province.

Provincial Police Chief General Aqa Noor Kentoz said that all four had been shot and killed at a checkpoint on the outskirts of Lashkar Gah, the provincial capital. He added that the four officers might have been attacked by an insider.

No one immediately claimed responsibility for the assault.

ss/jlw (Reuters, dpa, AP)