Foreign militants are assembling in Pakistan’s wild western tribal areas preparing to assault international soldiers across the border in Afghanistan, according to a former al-Qaeda operative recently captured by NATO forces.

The British newspaper Daily Telegraph reported that the captive, described as a Moroccan man, has spoken to investigators about how he helped foreign fighters cross into Afghanistan.

The International Security Assistance Force (ISAF), the NATO-led security mission in Afghanistan which was formed by the United Nations Security Council to fight the insurgency, said in a statement: After his capture the facilitator provided details about his personal travel from Germany. He also observed foreigners from many countries converging in Pakistan to conduct attacks against coalition forces in Afghanistan.

According to the report, the Moroccan witness was living in Germany and travelled through Iran and Pakistan to reach Afghanistan.

NATO officials fear that an increased number of foreign insurgents will likely take vengeance on its forces in Afghanistan for the assassination of Osama bin laden in a Pakistani compound three weeks ago.

Thus far, most of the revenge attacks have taken place in Pakistan, including a car bomb Wednesday in Peshawar which killed five people and destroyed a police station.

However, the mountainous border regions between the two countries has long been believed to be a haven for al-Qaeda and other terrorist groups. The area’s remoteness and isolation makes it difficult for western coalition troops to enter it. Instead, US and NATO forces that relied on dropping unmanned drone missiles to target and kill suspected militants hiding in the territory.