Washington, Aug 30 (IANS): Acknowledging that Washington's counter-terrorism cooperation with Islamabad has "not always been smooth," the United States has said it would continue to work with Pakistan to rid the region of Al Qaeda.

"Beyond saying that our work, our counterterrorism work with Pakistan, continues, that these issues have not always been smooth," State Department spokesman Victoria Nuland told reporters Monday in response to a question

"Sometimes our work together is complex, but we share an interest with Pakistan in ridding the region of Al Qaeda. And that work will continue," she said when asked what action Pakistan was taking against terrorist groups like Al Qaeda and Lashkar-e-Taiba (LeT) blamed for 2008 Mumbai terror attacks.

Asked if Pakistan had taken any concrete steps to fight terrorists, Nuland repeated: "Well, I'm not going to get into the details of our very sensitive counterterrorism cooperation with Pakistan.

"But as I said, we share an interest with Pakistan in ridding that country, that region, of Al Qaeda. We've worked on it together for many years, and our work will continue."

Asked specifically what Pakistan was doing to bring the perpetrators of Mumbai attacks to book Nuland said: "I think I've said what I'm going to say on counterterrorism cooperation with Pakistan."

The spokesperson also declined to comment on Pentagon's statement that "nerve center" of Al Qaeda lies in Pakistan though the recent killings of Osama bin Laden in May and now its number two Atiyah abd al-Rahman has dealt the global terror group a severe blow.

"Al-Qaeda in Pakistan clearly remains a nerve centre of the organisation, remains dangerous. They have suffered significant losses in recent years," Pentagon spokesman, George Little told reporters earlier.