A U.S. drone bombed a mud house in Pakistan’s rugged northwest on Thursday and killed six people, officials said, as the Pakistani military said it had seized control of 80 percent of a key city from the Taliban.

A U.S. drone bombed a mud house in Pakistan's rugged northwest on Thursday and killed six people, officials said, as the Pakistani military said it had seized control of 80 percent of a key city from the Taliban.

Drone strikes in Pakistan resumed after a six-month hiatus, days before the military launched an air campaign.

Previously, the city was largely under the control of the Taliban, said General Zafarullah Khan, the top commander in rugged North Waziristan, which borders Afghanistan.

The offensive in North Waziristan began on June 15, following months of failed negotiations between the government and the militants. Taliban attacks continued during the talks. A brazen assault last month on the airport in the southern city of Karachi killed 34.

The army then ordered the entire civilian population of North Waziristan - estimated to be around half-a-million people - to leave. The ground offensive was launched on June 30.

Since the air operation began, 400 militants have been killed and 130 injured, the military's public relations wing said. Twenty four soldiers had been killed and 19 injured. The extent of civilian casualties is unclear.

During Wednesday's trip arranged by the army, journalists toured underground tunnels and facilities that the army said were bomb-making factories and camps to train bombers.

The fighters, many of them ethnic Uzbeks and Chinese Uighurs as well as indigenous fighters, were completely on the defensive, Gen. Khan said.

Reports from local residents suggest that many militants moved out of the area before it was secured.