Thu Sep 27, 4:17 PM ET

WASHINGTON - The United States tightened sanctions Thursday on Myanmar's military rulers and urged countries like China and India to do more to help end a bloody crackdown on anti-government demonstrators.

As the US Treasury Department froze the US assets of 14 top junta members, the White House urged the regime to let Myanmar-bound UN envoy Ibrahim Gambari meet with protest leaders and detained democracy icon Aung San Suu Kyi.

In a previously unannounced meeting, US President George W. Bush told Chinese Foreign Minister Yang Jiechi he hoped China would "use its influence in the region to help bring a peaceful transition to democracy in Burma (Myanmar)," said US national security spokesman Gordon Johndroe.

Bush also thanked Yang, who was at the White House for talks with US national security adviser Stephen Hadley, for China's help in facilitating Gambari's visit to Myanmar, Johndroe said.

Earlier, the US president pointedly urged "all nations that have influence" with Myanmar to throw their weight behind global efforts to end the crackdown, which has left nine people dead including a Japanese journalist.

"I call on all nations that have influence with the regime to join us in supporting the aspirations of the Burmese people and to tell the Burmese junta to cease using force on its own people, who are peacefully expressing their desire for change," he said in a statement.

US officials did not deny that his message was largely aimed at China and India, Myanmar's potent neighbors, but cautioned against reading it as a sign that Washington was worried they may hobble pressure efforts.

Energy-hungry India and China, besides other Asian countries, have been jockeying for a share of Myanmar's vast energy resources, triggering accusations that this was weakening US and European economic sanctions.

Under existing sanctions, 375 members of the junta and their families are banned from entering the European Union and are subject to an asset freeze.

"The world is watching the people of Burma take to the streets to demand their freedom, and the American people stand in solidarity with these brave individuals," said Bush, who made a direct appeal to Myanmar security forces.

"I urge the Burmese soldiers and police not to use force on their fellow citizens. I call on those who embrace the values of human rights and freedom to support the legitimate demands of the Burmese people," he said.

White House spokeswoman Dana Perino urged the junta to give Gambari "full access to all relevant parties while he is in Burma beginning tomorrow. This includes those jailed by the junta, religious leaders and Aung San Suu Kyi."

The Nobel Peace Prize winner's opposition National League for Democracy won 1990 parliamentary elections, but the results were rejected by the junta, who have kept the 62-year-old activist under house arrest for most of the past two decades.

Meanwhile, the US Treasury Department tightened US sanctions, first imposed in 1997 and expanded in 2003, by freezing assets of top regime leaders, and a visa ban on alleged human rights violators and their families was pending.

Among those designated for sanctions were junta leader Than Shwe, who is minister of defense and chairman of the State Peace and Development Council (SPDC); Vice Senior General Maung Aye, commander of the army and vice chairman of the SPDC; Lieutenant General Thein Sein, acting prime minister and first secretary of the SPDC; and General Thura Shwe Mann, joint chief of staff and member of the SPDC, along with other senior officials and military officers.

The US State Department has been adding Myanmar officials, regime supporters, and family members to a list of people barred from entering the United States, Johndroe said.

On a more symbolic front, the White House also indicated that it would continue to refer to the country as "Burma" instead of "Myanmar" in a show of support for the pro-democracy activists there. The military government changed the name in 1989.