Taliban militants in Pakistan's tribal region of North Waziristan have pulled out of a peace deal negotiated with the government last year.
The announcement by a spokesman for local Taliban leader Hafiz Gul Bahadar Tuesday threatens to open another front for the Pakistani army - already battling the insurgents in two other areas.
The spokesman, Ahmadullah Ahmadi said Bahadar decided to withdraw from the deal because Pakistan had not put a stop to ongoing missile strikes from U.S. drones in North and South Waziristan. Bahadar also vowed to start attacking Pakistani security forces.
The collapse of the peace agreement came weeks after the Pakistani army began its campaign to hunt down Taliban leader Baitullah Mehsud in South Waziristan.
Mehsud is blamed for scores of attacks against government and civilian targets, and is believed to be a key facilitator for al-Qaida fighters in Pakistan.
Meanwhile, U.S. newspaper The New York Times says Washington and Islamabad have increased intelligence-sharing in the tribal area offensive.
The newspaper says U.S. surveillance aircraft are now providing the Pakistani military with live video and other information on militant activities in the region. It also says Washington is speeding the delivery of transport helicopters, body armor and other equipment to the Pakistani army.
Pakistani and U.S. officials have not publicly confirmed the alleged arrangement.
On Tuesday, the military said 18 suspected militants had been killed and 23 others detained in in the greater Swat valley. Three soldiers were killed and eight others wounded in the offensive.
In southwestern Baluchistan province, a car bomb explosion killed four people. The blast occurred near a road frequently used by trucks carrying supplies to foreign troops in neighboring Afghanistan.