The United States Army Secretary, Louis Caldera, has told survivors of a massacre during the Korean War he understood and acknowledged their suffering.

American troops are alleged to have killed hundreds of civilians in the incident at No Gun Ri, 200km (125 miles) from Seoul, during the first weeks of the war nearly 50 years ago.

US war veterans said publicly last year they had been ordered to machine-gun a group of refugees at No Gun Ri because it was suspected of including North Korean guerrillas in disguise.

Koreans have for many years said that this is what had happened.

But Mr Caldera warned it was too early to determine exactly what had occurred.

The army chief added that the US has no plans to broaden investigations into alleged Korean War atrocities beyond the No Gun Ri incident.

Massive task ahead

"Our commitment is to do a thorough review of the incident at No Gun Ri because of the central claim that makes No Gun Ri unique, and that is the claim that there was intentional taking of innocent life," said Mr Caldera.

The army chief said there were more than a million documents in Korean and American archives that needed to be reviewed, and troops who served in the area at the time had to be interviewed.

The compensation and punishments related to the case would depend on the nature of the mass killings, specifically on whether it was intentional, he added.

Mr Caldera was speaking after visiting the site of the massacre on Monday, where he talked with witnesses and relatives who said they had survived the killings.

US troops were stationed in South Korea at the head of a United Nations coalition defending the country after an invasion from the northern half of the divided peninsula in 1950.