The US has warned that anti-government elements in Laos may be planning to bomb a key Asian regional meeting there next month.
The US state department said the US embassy in Vientiane had information of possible attacks on the Association of South East Asian Nations (Asean) forum.
Asean, which groups 10 Asian countries, is meeting in the Lao capital from 25 to 30 November.
However, Laos' foreign ministry said the security concerns were unfounded.
"The US embassy in Vientiane has received information that during the Asean conference, persons associated with anti-Lao government groups may be planning to detonate several explosive devices in Vientiane," the US state department said.
Asean member countries
It urged US citizens in the country to "exercise extreme caution".
But Lao foreign ministry spokesman Yong Chantalangsy played down the fears.
"We thank the US government for letting us know this information, but there are absolutely no signs whatsoever of any weaknesses in our security system," Mr Chantalangsy told the AFP news agency.
"We won't let anyone undermine national unity."
The leaders of the 10 Asean members will be in Vientiane on 29 and 30 November for the annual summit.
A group called the Committee for Independence and Democracy in Laos said it carried out an explosion in Vientiane on 4 February that killed two people and another blast two days later in the southern town of Savannakhet during a meeting of Asean tourism ministers.
The group says it wants to end the Laos regime and Vietnamese influence in the country.