Pakistan has ordered its military to launch a full-scale offensive against the leader of the Pakistani Taliban and his militant network, an official says.
North West Frontier Province governor Owais Ahmad Ghani said troops had been told to eliminate Baitullah Mehsud.
Mr Ghani did not say when the operation in the north-west would begin, but he suggested that it was imminent.
Baitullah Mehsud's group are blamed for a string of deadly attacks in Pakistan, many of them in recent weeks.
Correspondents say the announcement of the operation in South Waziristan is likely to please the US.
Washington regards the tribal region as a particularly troublesome hideout for al-Qaeda and Taliban fighters suspected of attacks on US forces in neighbouring Afghanistan.
Baitullah Mehsud has his stronghold in South Waziristan, bordering Afghanistan, an area also rumoured to be the hideout of Osama Bin Laden.
Mehsud has been accused of involvement in the death of former Pakistani Prime Minister Benazir Bhutto - an accusation he denies.
'Crush the militants'
Mr Ghani told reporters in Islamabad on Sunday: "Baitullah Mehsud is the root cause of all evils.
"The Pakistan army and other law-enforcing agencies have been directed to crush the militants through a full-fledged and comprehensive plan."
The provincial governor said no political or religious party was supporting the Taliban. He also said there was no "foreign pressure" to launch military operations against them.
The BBC's M Ilyas Khan in Islamabad says Baitullah Mehsud is thought to head the most powerful group of militants in the country, with a network of alliances with other militants in the Orakzai, Bajaur and Malakand regions.
Any decisive offensive against Baitullah Mehsud would therefore be very significant as it could weaken the militants across the board, our correspondent says.
But analysts in Pakistan are puzzled over why the offensive has been publicised before being launched, removing any element of surprise.
There is also a question mark over why the announcement came from the NWFP governor, and not from someone higher up in the federal government.
Analysts point out that an operation against Baitullah Mehsud will require consensus across Pakistan's political spectrum, which only the central government can develop.
Army spokesman Maj Gen Athar Abbas told the Associated Press the military was "evaluating" the government's orders.
In the past, Pakistani army action has faltered or ended in truces that correspondents say have strengthened the militants.
Analysts say that in many ways a full-scale operation in South Waziristan would be harder than the recent fighting in the Swat valley, where Pakistani troops say they killed hundreds of militants in the past six weeks.
So far the armed forces have described their operations in South Waziristan as limited, compared with the high-profile offensive in the Swat valley further north.
But over the weekend the Pakistani air force went into action in South Waziristan and said they had killed 30 militants. There is no independent confirmation of the claim.
The announcement of the offensive against Baitullah Mehsud came after at least eight people were killed in a bomb attack at a market in the north-western Pakistani town of Dera Ismail Khan.
The explosives were reported to have been detonated by remote control after being hidden in a rickshaw.
The authorities blamed the attack on supporters of Baitullah Mehsud.
A spokesman for Mehsud has claimed that his group, Tehreek-e-Taliban Pakistan, has also been behind several other deadly attacks on Pakistani civilians recently, AFP news agency reported.
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