The United States is expected to announce new sanctions on Tuesday against Myanmar, where protests are growing against the ruling military junta, the White House said Monday.

In a speech to the United Nations General Assembly, U.S. President George W. Bush will set financial sanctions against key members of the regime and those who provide them financial aid, said the government's national security adviser, Stephen Hadley.

U.S. National Security Adviser Stephen Hadley said on Monday that sanctions were coming against Myanmar's military government.
(Lauren Victoria Burke/ABC News/Associated Press)

A visa ban will also be put in place against government officials and their families, said Hadley.

Over the past week, Buddist monks have led thousands in escalating anti-government protests, with the largest showing yet at a march on Monday in Myanmar's former capital, Yangon. Turnout estimates range from 50,000 to 100,000.

"It's very interesting what is happening in the country with the Buddhist monks who have joined this effort," Hadley said.

"Our hope is to marry that internal pressure with the external pressure coming from the United States and the United Nations and really all countries that are committed to freedom to try to force the regime into a change."

Hadley refused to specify what financial sanctions might be imposed.

"[Bush] will call for the United Nations and for other countries there to do all they can to support a process of political change in Burma," Hadley said.

The U.S. currently restricts imports, exports and financial transactions with Myanmar.

The protests were originally triggered by the government's decision to double the price of fuel in August, a decision that hit residents hard in the impoverished country.

On Monday, Myanmar's ruling military junta warned it would "take action" against the roughly 10,000 monks and thousands of other activists, who have staged what has become the country's largest anti-government challenge in nearly two decades.

The regime's warning served as a reminder of the brutal 1988 crackdown in Yangon, during which more than 3,000 pro-democracy demonstrators were gunned down in the streets.

Before this week's protests, 1988 was the last time Yangon saw such a large gathering of political dissenters.

With files from the Associated Press