Meanwhile, pro-Taliban fighters in the region are reported to have formally scrapped a controversial peace accord reached with the government last year.
Pamphlets distributed in Miranshah, the capital of North Waziristan, said: "We are ending the agreement today."
The Pakistani army has been moving in more troops into the tribal areas after Pervez Musharraf, the Pakistani president, said last week he would crush extremists and "root them out from every corner of the country".
Eight people were killed by suicide blasts on Thursday, followed by a Pakistani police discovery of a car packed with seven suicide vests, 100 mortar shells and other explosives in northwestern Dera Ismail Khan town on Friday.
Musharraf has provoked anger in the region after this week's army assault on a mosque complex in Islamabad that left at least 86 people dead.
Kamal Hyder, Al Jazeera's correspondent in Pakistan, says many analysts feel Musharraf is plotting a dangerous course in the region where the military is at risk of confronting its own people.
Hyder says his policies are not going down well and there is a definite risk that attacks in the area will increase.
General Assad Durrani, former head of Pakistani intelligence, told Al Jazeera: "If you look at the pattern of the last five to six years, ever since we joined the so-called 'war on terror', there have been enough warnings from the people of this area to suggest that there would be some reprisal attacks.
"The warning from the president may be now ... but experts had already said many years ago that this was likely to happen."
Source: Al Jazeera and agencies