George Bush was speaking while renewing wide-ranging financial and other sanctions against that country.
The extension of sanctions comes with the extension of a state of emergency regarding Myanmar - also known as Burma - that would have expired on Saturday. It has been in place since 1997.
Bush announced the extension in Yuma, Arizona, a US border area where he was visiting immigration facilities to press his request for tougher policies against illegal aliens.
"The crisis between the United States and Burma arising from the actions and policies of the government of Burma, including its policies of committing large-scale repression of the democratic opposition in Burma, that led to the declaration of a national emergency on May 20, 1997, has not been resolved," Bush said in a message to Congress.
"These actions and policies are hostile to US interests and pose a continuing unusual and extraordinary threat to the national security and foreign policy of the United States."
Thus, the state of emergency and sanctions will continue for a year.
UN urged to act
Tom Lantos, a leading House of Representatives human rights advocate and a strong critic of Myanmar's rights record, was pleased with the order but repeated an appeal for the United Nations to follow suit.
"Burma's military junta has escalated its attacks against the country's Karen ethnic minority, amid what was already a humanitarian nightmare," Lantos said.
Myanmar has been accused of
human rights violations
"I have long urged the UN to follow up with a meaningful resolution," the said.
Bill Clinton, the former US president, put the sanctions into effect in 1997 to punish the generals for their soldiers' repression against the democracy movement led by Aung San Suu Kyi, the 1991 Nobel Peace Prize laureate.
Then, Myanmar security forces were engaged in a nationwide crackdown on Suu Kyi's National League for Democracy. It already had arrested 316 members to keep them from going to Yangon, the capital, for a party meeting.
Suu Kyi’s arrest
Suu Kyi has spent most of the time under house arrest or in jail since she was arrested in 1990 after her party won elections. The military government nullified the results.
When the sanctions were declared, Suu Kyi and many of her followers were huddled in her lakeside compound, seeking shelter from the police.
Clinton's original declaration in 1997 prohibited new investment in Burma by Americans or US companies and imposed other sanctions.
Suu Kyi has spent most of her
time under house arrest or in jail
In July 2003, Bush tightened the sanctions with an executive order requested by Congress that imposed an import ban and prohibits exports of financial services to Myanmar and bans dealing in "property in which certain designated Burmese persons have an interest".