The Taliban have overrun a district in northern Afghanistan's Takhar province, and intense battles were underway Wednesday as government forces fought to retake it, an official said.

Six Afghan security forces were killed in the fighting over Darqad district, which borders Tajikistan, according to Sonatullah Taimor, the spokesman for the provincial governor. The area was not affected by the earthquake that struck northern Afghanistan on Monday, with its epicenter in the neighboring province of Badakhshan, he said.

The Taliban spokesman Zabihullah Mujahid emailed media organizations to say the battle for Darqad began at dawn Wednesday. Two Taliban fighters were killed, he said, as the insurgents captured government buildings, including police headquarters.

Afghan officials have said the Taliban have joined with other insurgents such as the Islamic Movement of Uzbekistan, and are spreading across the north with the aim of infiltrating Central Asian states.

In late September, this combined force took control of the capital of northern Kunduz province, also called Kunduz, and held it for three days before Afghan forces launched a counteroffensive.

The audacity of that attack took the Kabul government by surprise and highlighted weaknesses in intelligence and military organization nine months after international combat forces led by the U.S. withdrew from Afghanistan.

Some areas in Badakhshan that are suffering earthquake damage have a Taliban presence, officials have said, which could hamper relief efforts there.

The Taliban, responsible for thousands of deaths since launching their insurgency after their regime was toppled in a 2001 U.S. invasion, issued a statement Tuesday saying their fighters would help in the rescue and relief efforts in the earthquake-hit areas.