The Pakistani army on Thursday launched a major operation to nab Al Qaeda suspects in its tribal areas bordering Afghanistan.

The action followed US Deputy Secretary of State Richard Armitage's statement expressing doubts about Pakistan's commitment to fighting terrorism.

"Our forces have launched the operation early Thursday after receiving information that several Al Qaeda men are hiding there," Pakistan defence spokesman Major General Shaukat Sultan said.

The announcement of the operation came hours ahead of the scheduled arrival of Armitage and Assistant Secretary Christina Rocca to Pakistan. They have, however, put off their visit at the last minute.

Also see: Armitage, Rocca put off Pak visit

The operation followed observations by Armitage on Wednesday that Musharraf was supportive of a crackdown against Al Qaeda and the Taliban but it was not the case with all the army and security officials in Pakistan.

"I personally believe that President Musharraf is genuine when he assists us in the tribal areas and he has from inside of the border, but I do not think that affection for working with us extends up to down the rank of Pakistan security community," Armitage said in Washington.