WASHINGTON — President Bush on Friday reached further into his administration's limited arsenal of sanctions to apply against Myanmar, targeting additional senior officials and supporters. He also called on China and India to join international efforts to promote human rights and democracy in the military-run Southeast Asian nation formerly called Burma.

With his wife, Laura, who has taken a personal and public interest in the nation's political conditions, at his side, Bush said, "The people of Burma are showing great courage in the face of immense repression. They are appealing for our help. We must not turn a deaf ear to their cries."

The measures announced Friday follow two earlier efforts to put financial pressure on the leaders of Myanmar, who have shown no signs of forcing the military junta into relaxing its grip on the country's political life.

The steps Bush announced will freeze any U.S. assets of 16 additional government leaders and financial supporters. Fourteen leaders were listed under previous sanctions, as well as five Burmese companies and two from Singapore.

He also moved to tighten restrictions on trade with Myanmar involving certain sophisticated computers and equipment that can be used for civilian and military purposes.

The military regime that has ruled the country for 45 years has come under new pressure over the past month from demonstrations led by Buddhist monks and from diplomatic efforts originating in Washington and at the United Nations.

The special U.N. envoy to Burma, Ibrahim Gambari, has failed to gain promises from the junta leader, Gen. Than Shwe, to stop the bloody repression of opposition activists and other citizens who have taken part in street protests.

Derek Mitchell, a senior fellow at the Center for Strategic and International Studies in Washington, said that sanctions aimed at individual leaders and their supporters served to make life a little less comfortable for them without making it any more difficult for average citizens in Myanmar.

Bush, speaking to reporters in the White House Diplomatic Reception Room, praised the European Union and Australia for also imposing targeted sanctions on individuals in Myanmar, and he said he had asked "other countries to review their own laws and policies, especially Burma's closest neighbors — China and India, and others in the region."

Mitchell said India has been investing in natural resources in Myanmar, and China also has invested there and sells military equipment to the government.