The recovered Rembrandt self-portrait dates from 1630

It was retrieved on Thursday during an operation at a Copenhagen hotel that resulted in the arrest of four people.

"We heard that someone was trying to sell the painting and we decided to go for it," said a police spokesman.

The artwork - which was reportedly undamaged and still in its original frame - is worth an estimated £34m.

Dating from 1630, it was stolen by three armed and masked robbers who entered Sweden's National Museum in December 2000.

'Close co-operation'

Making off with three paintings - the Rembrandt and two others by Renoir - they escaped on a small motor boat, spreading nails in front of the museum before they fled.

It was stolen from Sweden's National Museum in December 2000

One of the Renoirs was recovered in 2001. Eight men were subsequently jailed for their part in the robbery.

Police said Thursday's raid came as a result of "close co-operation" between Swedish authorities, the FBI and the US Immigration and Customs Enforcement.

The four men arrested - two Iraqi nationals, a Gambian and a Swede - will face a custody hearing on Friday.

"Then we will have them extradited to Sweden," said Chief Superintendent Per Larsen of Copenhagen police.