President Bush announced Friday that he is expanding sanctions against Myanmar's military leaders in response to its crackdown against pro-democracy protesters.

Bush ordered the Treasury Department to freeze the financial assets of additional members of the repressive military junta. He also acted to tighten controls on U.S. exports to Myanmar, also known as Burma, and called on the governments of China and India to do more to pressure the government of the Southeast Asian nation.

"Monks have been beaten and killed. Thousands of pro-democracy protesters have been arrested," Bush said in the Diplomatic Reception Room of the White House.

"Burma's rulers continue to defy the world's just demands to stop their vicious persecution."

Last month, tens of thousands of people turned out for rallies, which started as protests of sharp fuel increases and later snowballed into the largest show of government dissent in decades. The junta claims that 10 people were killed when troops opened fire on demonstrators to disperse them, but diplomats and dissidents say the death toll is likely much higher.

In response, Bush imposed economic sanctions against more than a dozen senior officials in the Southeast Asian country, and he spoke at the United Nations to focus international attention on the repression.

The crackdown also prompted first lady Laura Bush to make personal appeals for support for Myanmar citizens, saying the acts of violence "shame the military regime."

Mrs. Bush joined him as he announced his new sanctions.

"He announced tighter sanctions that day and the possibility of additional action if the Burmese regime did not end its repression," White House spokesman Tony Fratto said. "Unfortunately the regime has not responded to the call from the international community."

The action taken by Treasury last month froze assets that the individuals targeted have sitting in U.S. banks or other financial institutions under U.S. jurisdiction. The order also prohibited any U.S. citizens from doing business with the designated individuals. Among those targeted for the sanctions were the junta leader, Senior Gen. Than Shwe, and the No. 2 man in the military regime, Deputy Senior Gen. Maung Aye.

The junta says it detained nearly 3,000 people in connection with the protests, that hundreds remain in custody and that it is still hunting for others. But the regime has released three prominent detainees, including the country's best-known comedian, as well as a popular actor and his wife.

On Thursday, the U.N. envoy to Myanmar said the country's military rulers could be offered incentives to move toward democratic reforms.

The envoy, Ibrahim Gambari, said one approach could be a combination of strong encouragement of the authorities in Myanmar to do the right thing along with some incentives to say "the world is not there just to punish Myanmar."

Earlier this month, Gambari met with the junta leader, Senior Gen. Than Shwe, and detained pro-democracy leader Aung San Suu Kyi, but he has so far failed to bring about a dialogue between the two sides.

The Associated Press contributed to this report.