Six Chinese travellers have been hurt when gunmen opened fire on a bus in Laos.
This is the third such attack in Laos in recent months, which seems to be targeting Chinese nationals.
The situation had already prompted a travel warning from the United States embassy in Vientiane.
State media reported gunman shot at a bus near the tourist town of Vang Vieng.
Reports said at least two people were shot in the head, and one is still classed as in a critical condition.
The bus was carrying 28 people from Kunming in southwest China en route to Vientiane.
The driver was also shot, the Xinhua news agency said.
A bomb explosion killed two Chinese nationals in January and another was killed in an attack in Luang Prabang province earlier this month.
Authorities in both Laos and China are mystified over the motive of the attacks, as no group has come out and claimed responsibility.