By Jonathan Head BBC South-East Asia correspondent

The two reporters - from France and Belgium - were apparently returning from a trip in the central mountains of Laos when they were arrested along with a US citizen of Lao origin, who was apparently acting as a guide.

They had been covering a little-known conflict between the Communist Government and ethnic Hmong rebels, who backed the Americans against Communist forces in Laos during the Vietnam War.

The two journalists have been charged with involvement in the death of a villager at the hands of what the authorities call bandits.

A foreign ministry statement also accused them of reporting while on tourist visas - although in secretive Laos, where the Communist Party has ruled unopposed for 27 years, this is the only way journalists can find out about sensitive issues.

Earlier this year two other journalists returned from the same area and reported that thousands of Hmong were living in terrible conditions in the mountains and being bombed by Lao and Vietnamese forces.

The government has always denied the existence of a Hmong rebel movement.

But two armed attacks on buses in a popular tourist destination earlier this year were widely believed to be the work of Hmong groups.

Hmong exiles in the United States frequently complain of repression inside Laos.

While the country remains closed to independent journalists, it is impossible to know the true picture.