ISLAMABAD, Pakistan (CNN) -- A suicide car bomber attacked a military checkpoint in northwest Pakistan on Monday morning, killing three soldiers, officials said.
The attack occurred in a village in the Swat Valley, two military sources said. They did not want to be named because they are not authorized to speak to the media.
Swat Valley, located in North West Frontier Province, was once Pakistan's biggest tourist destination. It is located near the Afghanistan border and about 300 km (186 miles) from the capital city of Islamabad.
In recent months, militants bent on imposing fundamentalist Islamic law, or Sharia, have unleashed a wave of violence across the North West Frontier Province and the valley that has claimed hundreds of lives, many of them security personnel.
The central government has long exerted little control in the area, but it launched an intense military offensive in late July to flush out militants.
As retaliation for the military presence, the Taliban has carried out a series of deadly bombings -- and said the attacks will continue until the troops pull out.
CNN's Reza Sayah contributed to this report.