As descendants of Titanic victims hold vigils, divers are plundering the wreck

Passengers participate in a memorial service, marking the 100th year anniversary of the Titanic disaster, aboard the MS Balmoral Titanic memorial cruise ship (AP)

New rules are needed to stop divers plundering the wreck of the Titanic, says Dr Robert Ballard, who found the ship nearly 27 years ago.

The US oceanographer lectured at the Titanic Belfast visitor centre on Saturday about pillaging from the wreck. He cited the crow's nest and a light fixture as items that had "gone".

"You don't stick your finger in the Mona Lisa when you go to the Louvre," he said. Dr Ballard displayed photos to the audience showing areas where rust on the ship had been disturbed by what he believes to be robotic submarines landing on its surface.

"I have no problem with people visiting the Titanic," he said, "if we can get some rules to visitations then that's what we need to do."

Titanic's wreckage in the North Atlantic is protected under a Unesco convention as a site of cultural heritage. The convention aims to stop the illegal pillage of sites.

Doctor Ballard's comments came during events to mark the 100th anniversary of the sinking of the Titanic. A minute's silence was held in Belfast yesterday as a monument was opened to remember the disaster, which claimed more than 1,500 lives.

A descendant of the ship's doctor helped unveil plaques inscribed with the names of 1,512 crew and musicians who died when the liner hit an iceberg on April 15, 1921. Jack Martin, the great, great nephew of Dr John Simpson joined Belfast Lord Mayor Niall O'Donnaghaile and a representative of the shipyard where Titanic was built to lay wreaths at the memorial.

The 12-year old also helped unveil five bronze plaques. A letter written on board the ship by the doctor to his mother will be brought to the city for exhibition.

He said: "I am proud that I am keeping the memory of my ancestor alive and it keeps memories fresh."