CIA agents lived in spy house near Bin Laden's compound for MONTHS in most intricate operation in agency's history

The CIA spied on Osama bin Laden for months from its own top-secret safehouse in Abbottabad, it has been revealed.

In one of the most intricate intelligence operations in CIA history, spies moved in to a property next door to Bin Laden's fortified compound to establish his 'pattern of life'.

The surveillance operation was so extensive that the CIA was forced to go cap in hand to Congress in December to ask for tens of millions of dollars more funding, which was met by creaming money from a variety of other agency budgets.

U.S officials refused to reveal how many agents were part of the close-quarters surveillance team but were at pains to stress the remarkable levels of care required because Bin Laden would flee the moment suspicions were aroused.

They used every possible means to gather information, including Pakistani informants, satellite images, telephoto lenses and listening devices in an attempt to record Bin Laden and his cohorts.

However, Bin Laden was so adept at hiding that the CIA admit to admiring his commitment, having rejected the suspicious-looking trappings of bodyguards and vehicles.

According to Pakistan security officials, the al Qaeda leader spent the last five years living in the same room of his mansion where he was shot and killed by U.S. forces.

The claims were made by the terrorist leader's wife, who apparently told interrogators that she and her husband had not left the same room for the past half a decade.