Obama becomes first sitting US president to visit Laos

Barack Obama became the first US president to visit Laos in office, touching down in Vientiane Monday for a summit of East and South East Asian leaders.

Obama arrived in the capital, where the tropical rain did not prevent a large number of airport workers coming out to greet him and cheering -- before being hushed by an official.

The outgoing president's visit comes decades after the United States launched a massive and secret bombing campaign in the country that lasted from 1964 to 1973.

More than two million tonnes of bombs were dropped. About 30 percent did not explode and are still causing casualties today.

During the trip Obama is expected to announce the ramping up of a US programme to clear unexploded devices, echoing similar moves Washington took in Vietnam as relations between the two former foes blossomed.

"Symbolically, it is important," Obama said of hours before his visit.

"At the outset, as we?re trying to build trust, a lot of work can be done around war legacy issues. For the Lao, that involves dealing with unexploded ordnance, which is still plaguing big chunks of the countryside."

"We should help."

Obama's visit to Laos will be the final trip to east Asia of his eight-year presidency, during which he has sought to refocus American military, political and economic resources on the region.

He will travel to the ancient capital of Luang Prabang on Wednesday, visiting a historic temple and meeting with students at a university growing up in a tightly controlled communist nation.