Malaysia's maritime authorities have detained a Chinese-flagged cargo ship amid reports this month that scavengers targeted two British World War Two wrecks off the coast of Malaysia—the HMS Prince of Wales and HMS Repulse—which were sunk by Japanese torpedoes in 1941.

An inspection of the cargo ship led to the discovery of old steel and cannon shells believed to have been scavenged from the HMS Prince of Wales. The shells could be linked to a separate seizure by police at a Johor jetty last week of multiple unexploded World War II-era artillery.

The Malaysian Maritime Enforcement Agency (MMEA) stated that it was working with Malaysia's National Heritage Department and other agencies to identify the ordnance discovered.

Worst disaster

HMS Prince of Wales was a King George V-class battleship—the most modern British battleships in commission during the Second World War. In its final action, the vessel attempted to intercept Japanese troop convoys off the coast of Malaya when it was sunk alongside the battlecruiser HMS Repulse by Japanese aircraft on 10 December 1941, two days after the attack on Pearl Harbor.

Their sinking is considered one of the worst naval disasters in the history of the Royal Navy. It was also one of the first battles to show that even the most powerful of modern warships—the Prince of Wales was  commissioned less than a year before it sank—were vulnerable without supporting air power.

Designated war graves

A spokesperson for the UK Ministry of Defence in London said: "We strongly condemn any desecration of any maritime military grave. Where we have evidence of desecration of the wrecks of Royal Navy vessels, we will take appropriate action, including working with regional governments and partners to prevent inappropriate activity at such sites."

“We are distressed and concerned at the apparent vandalism for personal profit of HMS Prince of Wales and HMS Repulse,” said professor Dominic Tweddle, director general of the National Museum of the Royal Navy, in a statement.

“They are designated war graves. We are upset at the loss of naval heritage and the impact this has on the understanding of our Royal Navy history.”

Repeatedly looted

The British vessels, on the sea bed some 100km (60 miles) off the eastern coast of Malaysia, had been targeted for decades. The shipwrecks are targeted by scavengers for their rare low-background steel, also known as "pre-war steel." The low radiation in the steel makes it a rare and valuable resource for use in medical and scientific equipment.

In October 2014, the Daily Telegraph reported that both Prince of Wales and Repulse were being "extensively damaged" with explosives by scrap metal dealers.