Japanese corporation Mitsubishi has issued an historic apology for forcing American prisoners of war (POWs) to work in its mines during World War II.

While Japan's government has formally apologised to American POWs in 2009 and again in 2010, Sunday's move by Mitsubishi was the first made by a Japanese corporation.

The apology came 70 years after the war ended.

During World War II, 12,000 American prisoners were shipped to Japan and employed as slave labour, including 500 who were forced to work for Mitsubishi's predecessor, the Mitsubishi Mining Co.

Hikaru Kimura, a senior executive of the firm, extended a "most remorseful" apology to 94-year-old James Murphy of California, who is among only two of the surviving US prisoners.

Murphy accepted the "gracious" apology and said he hoped it could help heal nations.

Murphy said the prisoners were held in conditions of "slavery", without food, clothing, and sanitation.

"For 70 years since the war ended, the prisoners of war who worked for these Japanese companies have asked for something very simple, an apology," he said.

'Very sincere'

"I have listened to Mr Kimura's apology and found it very sincere.

"We would hope to extend Mitsubishi's gracious coming forward at this time to all the other mines and factories who employed American prisoners against their will."

Al Jazeera's Rob Reynolds, who attended the ceremony at Simon Wiesenthal Center's Museum of Tolerance in Los Angeles, said while it was an "emotional moment", it still didn't wipe the slate clean.

Thousands of other POWs, including from the Philippines, Korea, and China, were also forced to work for Mitsubishi during the war.

"There were also numerous other Japanese companies and also thousands of prisoners from Australia, Great Britain and other countries," our correspondent said.

"These are still difficult issues, especially between Japan and its neighbours, Korea and China."

However, Jan Thompson, an academic from Southern Illinois University whose father was a POW, told Al Jazeera that it took a lot of courage for Mitsubishi to come forward, especially as most of its former executives had died, for what became an "extraordinary moment in history".

"Mr Kimura was very sincere, he was honest and it was very clear it was coming from his heart. It was so heartfelt, at least half of the room was crying. It was an extraordinary moment in history but I wish that more [prisoners] were still alive," Thompson said.

"I would like to think the world's applauding Mitsubishi."