Washington: A US diplomat said that Pakistan must use its boosted military presence in lawless tribal regions to do more to fight extremists. But the official defended Pakistan's much criticised efforts to defeat Al Qaida and Taliban militants.

John Gastright, a deputy assistant secretary of state, told lawmakers on Wednesday of a growing threat of violence in Pakistan, a key US ally in the fight against militants in South Asia.

The United States, he said, believes Pakistan can do more in that fight. But he noted 100,000 Pakistani troops along the rugged Afghan border and praised Pakistan's soldiers for harassing terrorists in an area where they previously felt safe.

He testified that Islamabad "must now use these assets to take more effective action against extremists taking refuge there." When a lawmaker raised the most recent US National Intelligence Estimate, which says Al Qaida had become increasingly comfortable in Pakistan, Gastright commended Islamabad's comprehensive strategy to fight extremists.

Tensions rise

"The government of Pakistan is no friend of Al Qaida," he said. "No government has captured or killed more Al Qaida or Taliban extremists than the government of Pakistan." The House of Representatives subcommittee on South Asia hearing comes as security deteriorates in Pakistan and as tensions rise between Washington and Islamabad.

President Pervez Musharraf is facing increasing criticism from Washington that the country's tribal regions have become a haven for terrorists; Pakistan denies this.