ISLAMABAD: The Pakistani army expects Taliban and al-Qaeda fighters in the South Waziristan tribal region to put up 'tough resistance' against a military offensive, the army's chief spokesman said.

Maj. Gen. Athar Abbas also confirmed earlier reports that the military has completed preparations for the long-awaited offensive in the lawless northwest region bordering Afghanistan, but would not give a start date.

‘God willing, peace will again be restored in the area through a successful operation,’ he told a private television news channel on Tuesday.

South Waziristan is considered the main base for Pakistan's Taliban movement, and any operation to clear the region is likely to gain praise from the United States. US officials have long pressed Pakistan to eliminate safe havens on its soil used by militants to plan attacks on American and Nato forces in Afghanistan.

An operation in South Waziristan will face steep challenges, ranging from harsh terrain to well dug-in militants.

Pakistan's military said months ago it was planning an operation aimed at eliminating Baitullah Mehsud, the Pakistani Taliban chief, in South Waziristan. But the US killed Mehsud in a missile strike in August, and since then, there have been lingering questions over whether Pakistan would try to dismantle the rest of his network there.

Analysts say 10,000 well-armed militants, including foreign fighters, are in the region.

Abbas said the army had already tried to weaken the militants by surrounding them, blocking roads and targeting them through air strikes. The point was to weaken the militants before launching a full-scale offensive against them.

‘As we all know, this group and this organization has fighters and they will offer a tough resistance in this area,’ Abbas said.

Interior Minister Rehman Malik said the government was already targeting the Taliban in South Waziristan and ‘if needed, further action shall also be taken at an appropriate time' against militants in other areas along the Afghan border.

On the other hand, Washington has pressed Pakistan to crack down on the militants, and on Tuesday the top US commander in Afghanistan, Gen. Stanley McChrystal, met Pakistan military chief Gen. Ashfaq Parvez Kayani in Islamabad.

The Obama administration is debating whether to add up to 40,000 more troops to fight the resurgent Taliban in Afghanistan, but says it cannot win there unless Pakistan does more to fight militants on its side of the border.

The Taliban said they would repel any offensive against their strongholds.

On Tuesday, the Pakistani Taliban claimed responsibility for a suicide bombing at the World Food Program headquarters in Islamabad that killed five people. The attack on Monday prompted the UN to temporarily shut all its offices across the country. –Agencies