Younis al Mauritani, a senior al Qaida commander described by some to be the organization's "foreign minister", has been captured by Pakistani security forces, officials said Monday, the most important Al Qaida figure in several years to be arrested in Pakistan.

American intelligence was involved in the arrest. Al Mauritani, central to the group's plots against the West, was detained in the western city of Quetta, along with two other al Qaida operatives.

Since the discovery and elimination of Osama bin Laden in Pakistan by U.S. special forces, in May this year, there has been intense pressure on the Pakistani authorities to prove that they are committed to the fight against al Qaida. In the years immediately following the 9/11 attacks, a series of top al Qaida figures were captured in Pakistan but in more recent times, those arrests had dried up.

"Al Mauritani was tasked personally by Osama Bin Ladan to focus on hitting targets of economical importance in United States of America, Europe and Australia,” said a statement from the Pakistani military. “He was planning to target United States economic interests including gas/oil pipelines, power generating dams and strike ships/oil tankers through explosive laden speed boats in international waters."

The arrest of al Mauritani was “planned and conducted with technical assistance” from American intelligence agencies, the Pakistani military said, showing that anti-terror cooperation is continuing, despite the deep tensions that emerged between Islamabad and Washington following the death of bin Laden.

The detention also confirmed that many of al Qaida's top leadership remains in hiding in Pakistan. American officials have sought the aid of Pakistan after the death of bin Laden, sensing that the organization can be dealt a fatal blow as it struggles to cope with the death of its leader.

Al Mauritani was reportedly planning a massive attack in Europe, which triggered a terror alert in Germany late last year.

Quetta, the provincial capital of Baluchistan, close to the border with Afghanistan, is famous as the supposed headquarters of the Afghan Taliban leadership, known as the “Quetta Shura”. The city’s association with al Qaida is much less known.