Islamabad  - Pakistani security forces have arrested an al-Qaeda operative believed to be linked with the July 2005 London terror attacks which killed 52 people and wounded hundreds more, an intelligence official said Thursday.

Zabi-ul-Taifi, a Saudi national, was seized along with six suspects Wednesday in a raid by paramilitary troops near Peshawar city, the capital of North-West Frontier Province.

"It was a swift operation and the foreigners were captured without any violence," the official said on condition of anonymity.

He used the term foreigners as all detainees were either Arabs or Afghans. They were staying in the house of an Afghan at the border with the lawless Khyber tribal district, which adjoins Peshawar.

There was no immediate official confirmation of Taifi's arrest. However, local administrators said security forces have launched a crackdown on militants attacking NATO supplies passing through Khyber.

According to residents, some Westerners monitored the operation while at least one US pilotless aircraft drone was seen circling the area during the action. But the intelligence official declined to comment on the reports.

Taliban sources tried to downplay the significance of the arrests. "These were common workers of an Islamic non-governmental organization Ikhwanul Muslimin [Muslim Brotherhood] that conducts welfare work in the area," said a local Taliban leader.

Taifi is suspected of plotting the London bombings on July 7, 2005. (dpa)