Pakistan launches ground offensive

The US pushed the government to carry out the assault in South Waziristan and comes after two weeks of militant attacks which left more than 175 people dead.

Pakistan has fought three unsuccessful campaigns since 2001 in the region, which is the nerve-centre for Pakistani insurgents fighting the US-backed government.

It is also a major base for foreign militants planning attacks on American and Nato forces in Afghanistan and on targets in the West.

After months of aerial bombing, on Saturday troops moved into the region from several directions, heading to the insurgent bases of Ladha and Makeen among other targets, intelligence and military officials said. The operation was expected to last around two months.

Pakistani army spokesman Maj Gen Athar Abbas confirmed a fully-fledged ground operation was under way, and said that it aimed to "uproot" the Pakistani Taliban. He said it was too early to discuss what sort of resistance the army was meeting.

The United Nations has said it is preparing to help civilians that are fleeing the region. Up to 150,000 civilians have already left in recent months after the army made clear it was planning an assault, but there are perhaps as many as 350,000 remaining.

The military has already said it has sealed off many supply and escape routes and has been trying to secure the support of local tribesmen in the fight.

Speaking earlier in the week, army spokesman Abbas said the assault would be limited to the late Pakistani Taliban leader Baitullah Mehsud's holdings - a swath of territory that stretches roughly 1,275 square miles. That portion covers about half of South Waziristan.

The plan is to capture and hold the area where Abbas estimates 10,000 insurgents are based and reinforced with about 1,500 foreign fighters.