The US has said it will back a fresh Pakistani military crackdown on al-Qaeda and Taliban activity.
The move effectively puts pressure on the Pakistan government to use the momentum from last week's assault on the pro-Taliban Red Mosque in Islamabad to launch a decisive operation along its northern frontier.
Force has rarely been a successful policy in the tribal areas, which cover about a third of the porous 2,500km border between Pakistan and Afghanistan.
The region shelters thousands of the 'jihadis' who battled the Soviet occupation of Afghanistan in the 1980s and welcomed back Taliban and al-Qaeda militants who fled the US-led invasion of Afghanistan.
Army operations against insurgents in North Waziristan and neighbouring South Waziristan have left more than 700 soldiers and 1,000 militants dead since 2004.
The US pledge of support follows the killing of more than 60 people, most of them paramilitary soldiers and police, in the past two days.
On Saturday, a suicide bomber launched the first in a series of attacks by driving an explosives-packed car into a paramilitary convoy in North Waziristan, leaving 24 dead.
Early Sunday, a second convoy was hit in the Swat Valley, where troops were deployed last week after a radical imam called for jihad on local radio.
Two explosives-laden cars struck the military vehicles within three minutes, killing 12 security personnel, a petrol station attendant and a family of four.
Later in the day another attacker at a police recruitment centre killed at least 26 police officials and recruits when he set off explosives strapped to his body.
