SECRET budget documents show that a US military lab in Afghanistan analysed DNA from Osama bin Laden's corpse and confirmed his identify shortly after he was killed by a Navy commando team.

The Pentagon denied more than a year ago it had any records of these tests in a response to a Freedom of Information Act request filed by The Associated Press a day after President Barack Obama announced bin Laden's death.

The Washington Post reported on Thursday that classified intelligence budget files provided by National Security Agency leaker Edward Snowden state that a forensic intelligence lab run by the Defence Intelligence Agency performed the DNA testing.

The Post reports that the tests "provided a conclusive match".

Bin Laden was killed at his Pakistan hideout in May 2011.