Japan's ambassador offered a personal apology to survivors of the notorious Bataan Death March in World War II as they met for the last time, a veterans support group said.
Thousands of US and Filipino prisoners of war are believed to have died when Japanese soldiers forced them in 1942 to trudge some 100 kilometers (60 miles) through tropical heat with little food or water.
The surrendering troops suffered casual beheadings and bayonet stabbings inflicted by the victorious forces, in what was ruled as a war crime after Imperial Japan's surrender.
Japan's ambassador to Washington, Ichiro Fujisaki, made a surprise visit to personally apologize to Bataan Death March survivors who gathered in San Antonio, Texas for what they expect to be their last reunion.
"We extend a heartfelt apology for our country having caused tremendous damage and suffering to many people," Fujisaki told them, according to the US Army Freedom Team Salute, which supports veterans.
The Japanese embassy in Washington said it did not have a transcript of Fujisaki's remarks during the ceremony on Saturday.
Seventy-three veterans turned out for the reunion, some of them bedridden, he veteran support group said in a statement.
US military officials also flew from Washington to Texas to present commendations to the veterans.
Japan, transformed after World War II into an officially pacifist US ally, has repeatedly apologized for wartime abuses, but the ambassador's trip to Texas was an unusually personal touch.
Japanese leaders when discussing the war generally repeat a landmark statement of apology approved by the cabinet in 1995 on the 50th anniversary of Emperor Hirohito's surrender.
Wartime issues -- which long haunted Japan's relations with its neighbors -- have occasionally creeped into Tokyo's alliance with Washington as well. In 2007, lawmakers demanded a new apology for Japan's use of wartime sex slaves.