Pakistan's military is beginning a significant move into South Waziristan, where the
Tehrik-e-Taliban Pakistan - or the Pakistani Taliban - are based, US officials have said.
The operation is said to be targeting Baitullah Mehsud, the leader of the Pakistani Taliban, and will be carried out with greater support from the US.
Witnesses and intelligence officials said Pakistani aircraft had bombed a stronghold of Baitullah Mehsud on Saturday, the Pakistani Taliban leader, in the South Waziristan.
"Four fighter jets bombed parts of Makken early on Saturday but we don't know about the extent of damage or any casualties," Mohammad Khan, a shopkeeper in the area said.
Pakistan's Geo TV reported that large numbers of people were migrating from South Waziristan to North Waziristan.
"Operations that appear to be under way now would be the largest operations that have been undertaken in Waziristan," a US defence official said on Friday.
"We think that the initial phases of that operation have already begun."
Pakistan says it has almost completed an offensive to drive Taliban fighters out of the Swat Valley, an area to the north of Waziristan in North West Frontier Province (NWFP).
Fight 'to the end'
Asif Ali Zardari, the Pakistani president, said on Saturday he would fight the Pakistani Taliban "to the end".
"We are fighting a war for our sovereignty. We will continue this war until the end, and we will win it at any cost," he said.
"These people want to capture the institutions of Pakistan by spreading terrorism and by intimidating the people.
"They have killed thousands of innocent people."
Zardari's comments came after two suicide bomb attacks on Friday, claimed by the Pakistani Taliban, in Lahore and Nowshera, in NWFP, killed at least eight people, including a pro-government religious leader.
Maulana Sarfraz Naeemi, known to oppose the Taliban, had condemned the use of suicide bombings.
The US defence official said on Friday that the Pentagon expected Pakistan to conduct "fairly significant combat operations in South Waziristan".
Another US official said Taliban and al-Qaeda leaders were "under very significant pressure", while a third US official said the US would be providing increased intelligence and surveillance support to Pakistan.
Pakistan's recent operations have been under way for six weeks, taking the military first into Buner and Upper Dir districts, then into the Swat Valley.
The first US official warned that "isolated pockets of resistance still remain" in parts of the Swat valley as the Pakistani army worked to finish the two-month campaign, and that Islamabad needed to brace for more attacks.
"[Mehsud] has turned suicide bombing into a production output not unlike Toyota outputs cars," the official, who described the Mehsud as leading an extensive network of religious schools that sold or bartered child suicide bombers in NWFP, said.
The key element of the US Afghanistan-Pakistan strategy, the defence official said, is to have troops put pressure on al-Qaea and Taliban fighters believed to be operating out of safe havens in Waziristan.
From Al Jazeera.
First a president was elected who is extremely popular in the Muslim world, then that president gave a speech that surpassed their wildest hopes, then al-Qaeda announced that it's broke, and now Pakistan has finally, at long last, taken the fight against the Islamic Emirate of Waziristan and its allies to Waziristan itself. Meanwhile, troops and development projects pour into Afghanistan, and public opinion in Pakistan turns against the TTP.
Could this be the beginning of the end?