Most have been linked to the sectarian strife between majority Sunni and minority Shiite Muslims.

The city also borders the South Waziristan tribal district, a stronghold of top Taliban commander Baitullah Mehsud.

Pakistan's government announced last month that troops had been asked to eliminate Mehsud and his network. Although dozens of airstrikes and shelling campaigns have been carried out since then, a full-fledged ground offensive has yet to begin.

Mehsud carries a $5 million US bounty on his head for being 'a key Al Qaeda facilitator' and tops Pakistan's list of most-wanted terrorists.