ISLAMABAD, June 16 An American construction worker detained in Pakistan while on a solo mission to kill Osama bin Laden claimed on Wednesday that he was obeying an order from God to avenge the Sept 11, 2001, attacks, said security officials.

Gary Brooks Faulkner said God revealed the order in one of his dreams, prompting him to travel to Pakistan in search of Al Qaeda's leader, said two security officials, one of whom is part of a team of investigators questioning the American.

Catching Osama bin Laden was 50-year-old Faulkner's passion, his brother Scott Faulkner said. A devout Christian with a prison record, Faulkner has been to Pakistan at least six times, learned some of the local language, and even grew a long beard to blend in, according to relatives and acquaintances.

“Our military has not been able to track Osama down yet. It's been 10 years,” Scott Faulkner told reporters in Denver. “It's easier as a civilian, dressed in the local dress, to infiltrate the inside, the local people, gain their confidence and get information and intel that you couldn't get as an American soldier, Navy SEAL, whoever you might be.”

Gary Faulkner, of Greeley, Colorado, arrived on June 3 in the town of Bumburate. He was assigned a police guard, as is common for foreigners visiting remote parts of Pakistan. When he checked out of a hotel without informing the guard, officers began looking for him, senior police official Mumtaz Ahmad Khan said.

Faulkner was found in a forest.

“We initially laughed when he told us that he wanted to kill Osama bin Laden,” Khan said. But when officers found weapons, including a 40-inch sword and a pistol as well as night-vision equipment, “our suspicion grew”.

He said Faulkner was trying to cross into the nearby Afghan region of Nuristan, one of several rumoured hiding places for Osama bin Laden along the rugged Afghan-Pakistan border.

Faulkner's sister, Deanna M. Faulkner of Grand Junction, Colorado, said her brother suffered from kidney disease that left him with only 9 per cent kidney function. “I'm worried about him. I'm worried that in Pakistan they won't give him his dialysis and if he doesn't get it, he's in serious trouble,” she said.

A doctor examined Faulkner and determined his current condition was not life-threatening, the Pakistani security officials said.

US Embassy spokesman Rick Snelsire said American officials were seeking consular access to a US citizen in Pakistani custody and that once given, they could help arrange for medical care.

Scott Faulkner said his brother sold all his tools to finance his trip and was prepared to die in Pakistan. He said Faulkner had a travel visa, obtained his weapons inside Pakistan and only took with him a Bible and plastic handcuffs.

Gary Faulkner, who is being questioned in Peshawar, has not yet been charged with any crime in Pakistan.—AP