Thailand’s government has been urged to lift a state of emergency and drop terrorism charges against leaders of recent anti-government protests.
The International Crisis Group (ICG) warned the “legitimate frustrations” of protesters were “being forced underground and possibly towards illegal and violent actions”.
The decree has been in place since a bloody military crackdown on 19 May.
Thailand’s prime minister told the BBC the situation was being addressed.
Ninety people died and 2,000 were injured during the two months of protests, which blocked off the commercial centre of Bangkok.
More than 400 people have been arrested under emergency law, which has handed sweeping powers to the police and military.
The leaders of the so called “red-shirt” anti-government movement are still in prison on charges which carry the death penalty.