A suicide bomber has killed at least 24 Pakistani soldiers in the remote and volatile tribal area near the Afghan border.
An army spokesman said 29 other troops were also wounded when a car packed with explosives was driven into a military convoy in north Waziristan.
Initial reports had said that 13 soldiers had been killed when the bomber struck the convoy around 50km north of the region's main town, Miran Shah.
Major General Waheed Arshad said the death toll could rise since troops were searching for one of four vehicles attacked that rolled off the road.
The attack is the latest deadly incident to hit the region over the last few days.
Opposition
Two suicide blasts killed eight people on Thursday, and police on Friday said they seized three men and a car packed with seven suicide vests, 100 mortar shells and other explosives in northwestern
Pervez Musharraf, the Pakistani president, has provoked anger in the region after this week's army assault on the pro-Taliban mosque complex in
Musharraf however has warned he would root out what he calls extremists and has deployed extra troops to the border areas with
Kamal Hyder, Al Jazeera's correspondent in northwest
Hyder says his policies are not going down well and there is a definite risk that attacks in the area will increase.
Thousands of Islamic protesters on Friday called for jihad and burnt effigies of Musharraf and a puppet of "Uncle Sam".
The Pakistani president is a strong supporter of the US-led "war on terror."
PHOTO CAPTION
Anti-government protest in the tribal northwest region