The tail houses the "black boxes" - the voice and flight data recorders - which could give investigators clues as to the cause of the crash. It was found in a secondary search area, lending weight to theories that strong currents have moved the debris.

The plane was lost en route from Surabaya, Indonesia, to Singapore on 28 December, with 162 people aboard.

No survivors have been found.

"We have found the tail that has been our main target today," search and rescue chief Bambang Soelistyo told reporters in the capital, Jakarta.

"I can ensure that this is part of the tail with the AirAsia mark on it."

The tail was spotted by teams involving divers and unmanned underwater vehicles, he said. It is the first significant piece of wreckage from the crash to be identified. He added that despite powerful sea currents and murky water, searchers had managed to take photographs of what appeared to be debris underwater. On one piece, the letter A appears to be painted.

Only 40 bodies have been recovered so far but the authorities believe many of the passengers may still be strapped inside the main body of the plane.

(BBC)