Bangkok - The United States issued a warning Friday urging Americans to avoid a central Laos province popular with adventure travellers after a sudden spate of deadly bomb and gun attacks.
Two roadside attacks killed three people last month in Xaisomboun province.
Those attacks followed a series of shootings at the end of last year, according to the notice published by the US Embassy in the capital Vientiane.
"The US Embassy in Vientiane has prohibited its personnel from travelling to Xaisomboun province, and encourages US citizens to adopt similar security measures," the travel alert said.
Chinese state media last month said two Chinese nationals were killed and one injured in a suspected bomb attack in the mountainous province, without speculating on the motive.
One of the victims was an employee of a mining company based in China's Yunnan province, which borders Laos.
Beijing has been sinking money into the sleepy Southeast Asian nation, a fellow communist state, in recent years and became its largest investor in 2014.
China also hoovers up landlocked Laos' water and forestry resources.
The US Embassy's alert Friday also reminded travellers that unexploded ordnances are still found throughout rural Laos.
During the Vietnam war US warplanes dropped more than two million tonnes of explosives across the landlocked country in an effort to cut North Vietnamese supply lines.
An estimated 30 per cent of the devices failed to detonate and 50,000 people have been killed by the explosives since the end of the war.
In a rare state visit to the cloistered communist nation last month US Secretary of State John Kerry said Washington was considering increasing the US$15 million fund it provides to tackle the scourge.