President Bush has signed into law a bill that extends a ban on all imports from military-ruled Burma.
The measure, approved by the U.S. Congress last week, renews import sanctions on Burma for another year.
In supporting the bill, U.S. lawmakers have cited Burma's suppression of human rights and political dissent.
Republican Senator Mitch McConnell, a chief sponsor of the measure, has said the sanctions show the people of Burma are not alone in their struggle against the military government.
Democratic Senator Diane Feinstein, a co-sponsor of the measure, has said the military government is holding some 13-hundred political prisoners. She called on Burma to release them, including democracy leader Aung San Suu Kyi.
Aung San Suu Kyi has been under some form of detention for most of the past 18 years.
Her political party, the National League for Democracy, won elections in 1990, but the government has never accepted those results.
Import sanctions were first imposed on Burma under a 2003 U.S. law. The United States also imposes an arms embargo against Burma, along with restrictions on exports and financial transactions.
Burma has been ruled by the military since 1962.