Sixty militants were reportedly killed as Pakistani security forces pounded bases of the Tehreek-e-Taliban, the main component of the Pakistan Taliban, from the air, and launched a three- pronged ground attack against them on Sunday.

Army officials said the army was concentrating on strongholds of the Tehreek-e-Taliban, in the northern area of South Waziristan. So far five soldiers have been killed in an operation that is the biggest such launched by the Pakistan army since 2003.

The ground forces have met stout resistance. Taliban militia armed with rockets and heavy weapons fought back hard at Sharwangi, an area of impenetrable forests high in the mountains.

“They’re trying to enter our land from all sides but we’ve repulsed their assault and they’ve suffered heavy losses,” Taliban spokesman Azam Tariq said. “The government has put the country’s sovereignty at stake to please (US President) Obama.” South Waziristan is part of the seven districts forming Pakistan’s Federally Administered Tribal Areas (FATA), which has greater autonomy than the rest of the country. The Taliban also have some bases in adjoining North West Frontier Province (NWFP).

About 28,000 troops moved against an estimated 10,000 Taliban fighters. The offensive followed a series of terror attacks across the country in less than a fortnight that left more than 170 people dead.

About 100,000 civilians have fled South Waziristan in anticipation of the offensive.