A top U.S. envoy has urged the Thai government to lift the state of emergency it has been under since April. Thai authorities say the strict controls are needed to prevent unrest while critics say they are being used to silence government opponents and limit freedom of expression. The U.S. envoy also urged Thailand to push its neighbor Burma for credible elections.

U.S. Undersecretary of State Bill Burns on Friday said he told Thai officials emergency decrees imposed on much of the country ought to be lifted as soon as possible.

The emergency powers allow the government to deploy soldiers to maintain order, detain people without charge for up to a month, and censor the media.

Thai authorities last week extended the state of emergency for Bangkok and 18 provinces for another three months. The government says the strict controls are needed to prevent unrest.

But speaking to an audience at Bangkok's Chulalongkorn University, Burns said it was in Thailand's own interest to lift the state of emergency. He said the decrees were not healthy for any democratic system.

"Now more than ever, it is critical for all Thai leaders to promote dialogue and reconciliation, to recognize the legitimate grievances of Thai citizens and to support the equal and impartial application of the rule of law," he said.

Thai authorities imposed the state of emergency after anti-government protesters in April broke into the Parliament building, forcing leaders to flee by helicopter.

Thousands of demonstrators occupied central Bangkok from March to May demanding the government step down and allow new elections.

Clashes between soldiers and protesters left 90 people dead, most of them civilians, and almost 2,000 injured.

The U.S. under secretary of State also urged Thailand to use its leadership in the region to press Burma for political reform ahead of elections expected later this year.

"The United States and Thailand have a shared interest in pressing for an inclusive, transparent, and credible electoral process. A first step toward this should be a genuine dialogue among all stakeholders and the release of more than 2,100 political prisoners including Aung San Suu Kyi," he said.

Aung San Suu Kyi's National League for Democracy won Burma's last elections, two decades ago, but Burma's military rulers ignored the results.

She has been kept locked up most of the time since and is banned from running for office.

Burma's neighbors, including Thailand, have been criticized for putting lucrative trade with the military government above human rights concerns.

The United States last year began a policy of engaging with Burma but maintains economic sanctions along with the European Union, Canada and other nations.