US President George W Bush has strongly criticised Burma's military leaders over recent arrests of dissidents protesting against a fuel price rise.
Dozens of protesters are now thought to be in custody
Mr Bush said that the protesters should be listened to rather than being "forcibly silenced".
Dozens of people have been arrested at small demonstrations around the country since the price hike on 15 August.
Analysts say it is an extremely rare display of public dissent in the military-ruled nation.
"I strongly condemn the ongoing actions of the Burmese regime in arresting, harassing, and assaulting pro-democracy activists for organising or participating in peaceful demonstrations," Mr Bush said.
"These activists were voicing concerns about recent dramatic increases in the price of fuel, and their concerns should be listened to by the regime rather than silenced through force."
The government doubled the price of petrol and diesel on 15 August. The price of compressed natural gas - used for buses - increased five-fold.
The move was not announced ahead of time and the reasons behind it remain unclear. But the increase has hit people hard in the impoverished nation.
Since then, there have been a series of protests, both in the main city, Rangoon, and in other towns around the country.
The demonstrations have continued despite the arrests of many of Burma's most prominent activists, who have been organising them.
Dozens of people are thought to be in detention and there are reports that some of them have begun a hunger strike.
Mr Bush urged the Burmese government to "stop its intimidation of those Burmese citizens who are promoting democracy and human rights".
Correspondents say although the protests are small, that they are continuing at all is remarkable given government attempts to end them.