President Bush imposed new U.S. sanctions on Thursday against property owned or controlled by the military junta in Myanmar.

Bush said in a statement that the regime "exploits and oppresses the people of Burma."

He signed an executive order that will block the property and assets of certain people and entities owned or controlled by the government of Myanmar, or officials of the government. The executive order expands existing authorities that allow the U.S. to target those responsible for supporting, empowering and enriching the Myanmar regime.

Myanmar, also known as Burma, has been under military rule since 1962.

Its government has been widely criticized for human rights abuses and suppression of pro-democracy parties such as the one led by Nobel Peace Prize laureate Aung San Suu Kyi, who has been under house arrest for more than a decade.

The ruling junta refused to honor the results of 1990 general elections won by Suu Kyi's party.

Last September at least 31 people were killed and thousands more were detained when the military cracked down on peaceful protests led by Buddhist monks and democracy advocates.

Dissidents in Myanmar and exile groups elsewhere have urged voters to vote on May 10 against the constitution, saying it is merely a ploy to perpetuate more than four decades of military rule.

"The people of Burma have long awaited the opportunity to live in a true democracy," Bush said. "The referendum vote scheduled for May 10, 2008 could have been that opportunity. However, Than Shwe and his regime are ensuring that the referendum vote will be on a dangerously flawed constitution, and will not be free, fair, or credible."