U.S. authorities revealed Friday that they are holding a high-level al-Qaeda figure who helped Osama bin Laden escape from Afghanistan.

The United States Department of Defence said in a release that "high-value detainee" Muhammad Rahimal-Afghani has been transferred to the U.S. prison in Guantanamo Bay, Cuba.

In a memo obtained by the Associated Press, CIA director Michael Hayden said al-Afghani was detained last summer. The memo suggested he was not captured by American authorities.

The CIA transferred al-Afghani to the Pentagon's custody this week, officials said, but declined to reveal when or where the prisoner had been captured.

A diplomatic official, speaking on condition of anonymity, said al-Afghani was captured in Lahore, Pakistan.

Hayden said al-Afghani's combat experience dates to the 1980s and included plots against U.S. and Afghan targets.

The Defence Department said al-Afghani had ties to al-Qaeda throughout the Middle East and was "one of bin Laden's most trusted facilitators and procurement specialists prior to his detention."

Department spokesman Bryan Whitman said the detainee helped prepare bin Laden's mountain hideout at Tora Bora when the U.S. mission in Afghanistan began in 2001, and later assisted the al-Qaeda leader's escape.

There are approximately 280 detainees at the Guantanamo Bay prison, including Canadian Omar Khadr, 21, who was captured in Afghanistan in 2002.

With files from the Associated Press