US President George W Bush has called on world leaders to increase pressure on Burma's rulers, as US officials moved to ban imports of Burmese gems.
The bill tries to prevent the military junta from laundering gemstones
Mr Bush, reacting to a UN report that confirmed at least 31 people died in a recent crackdown, said there could be no "business as usual" with the junta.
He said the US would lead efforts to place more sanctions on the regime.
Meanwhile US lawmakers have voted to stop Burma's rubies and high-quality jade from entering the United States.
The measure, passed by the House of Representatives, tightens sanctions against the junta by attempting to stop gem dealers from laundering their goods in third countries before they enter the US.
The bill, which must be approved by the Senate and president, also tries to stop Burmese leaders using US banks to launder money in third countries.
Democratic Rep Tom Lantos said in a statement: "Burma's generals fund this repression of their own people by selling off the country's natural resources, especially oil and gems, leaving the Burmese people in poverty."
He added that tightened sanctions would "ensure that the United States stands up to these thugs".
Mr Bush, who already imposed tough sanctions against the junta in October, pledged further action after a new UN report shed light on the scale of repression in Burma.
The UN's human rights envoy, Paulo Sergio Pinheiro, said at least 31 people had died as the ruling generals sought to regain control after a wave of peaceful protests swept the country in September.
"Mr Pinheiro's report demonstrates why the world cannot go back to business as usual with [Burma's leader] Gen Than Shwe and his junta," Mr Bush said in a statement.
"I call on all members of the international community to condemn the atrocities detailed in Mr Pinheiro's report in the strongest possible terms."