Taliban insurgents overran a district in one of the northern Afghan provinces hit by a powerful earthquake this week, underlining the security problems that have hampered efforts to get emergency relief to remote mountainous regions.

Officials said fighters seized control of the district capital of Darqand in Takhar province, on the border with Tajikistan in the early hours of Wednesday, continuing a campaign that has intensified across the country this year.

The area around Darqand is not one where there have been reports of major damage or loss of life from Monday's earthquake, which killed more than 300 people across broad swathes of northern Afghanistan and Pakistan.

But it is well within the impact zone and at least 15 people have been reported killed and more than 40 injured in Takhar province as a whole.

Abdul Khalil Asir, a spokesman for the Takhar police chief, said security forces had withdrawn from the district after six hours of fighting overnight.

He gave no information on casualties but Taliban spokesman Zabihullah Mujahid said in a statement that 12 police were killed and several wounded. Two Taliban militants were also killed and three wounded, he said.

The Taliban on Tuesday opened the door to allowing aid groups to bring emergency aid to victims of the disaster but continued fighting leaves big questions over how safely they would be able to operate.

With the thousands left homeless by the earthquake facing bitter winter weather, the need for emergency shelter and medical help has become urgent but authorities have struggled to gain a clear picture of the damage.

As well as the unstable security situation, landslides have cut roads and interrupted communications to many parts of the region, where thousands of houses were destroyed or damaged.

Two major roads, linking Taloqan, the capital of Takhar province, with the northern city of Kunduz, and Jalalabad in the east with the capital, Kabul, have been reopened after landslide debris was cleared, authorities said.