Burma's ruling military junta on Tuesday fired the country's prime minister, Gen. Khin Nyunt, a man seen by Asian leaders as the best hope for returning the country to democracy.

Khin Nyunt, who also headed Burma's powerful military intelligence organization, was placed under house arrest and charged with corruption, according to Thai officials, regional analysts and Burmese exiles with contacts inside the country.

He was replaced by Army Lt. Gen. Soe Win, considered to be part of a younger generation of hard-liners, who was reportedly involved in a May 2003 attack on supporters of the opposition National League for Democracy and its leader, Aung San Suu Kyi. Scores of people are said to have been killed in that attack.

Burmese state television and radio announced on the evening news that Khin Nyunt had been allowed to retire for health reasons. The retirement papers, the broadcasts said, were signed by the armed forces chief and former prime minister, Gen. Than Shwe, who heads the military junta.

The prime minister of neighboring Thailand, Thaksin Shinawatra, told reporters in Bangkok on Tuesday that Khin Nyunt had been "removed from his position." According to exiled Burmese activists and regional security analysts, Khin Nyunt had been forced out in an apparent bid by Than Shwe to consolidate power.

"The power struggle in the military has reached a climax, and the losers were the pragmatists," said Soe Aung, a spokesman for the Thailand-based National Council of the Union of Burma, a coalition of 30 exile and pro-democracy groups. "Prospects for democracy have deteriorated."

In Washington, Richard Boucher, the State Department spokesman, said: "The events that we're watching don't point in the direction of allowing freedom . . . of political and human rights."

Political leaders in Asia had hoped that Khin Nyunt would help build a policy of engagement for the reclusive regime, a policy they favored over the strong economic sanctions imposed by the United States.

Khin Nyunt, who built a reputation as a relative moderate in part by negotiating cease-fire agreements with 17 armed ethnic organizations, was opening talks with insurgents from Burma's Karen ethnic minority. He also was the main force behind talks with Suu Kyi, the country's most renowned opposition leader and a Nobel Peace Prize laureate, whose campaign for democracy has been targeted by the government. She has been under house arrest for nine of the past 15 years.

After Khin Nyunt was named prime minister last year, he announced a plan for restoring democracy, referred to as a "road map" toward eventual elections. Khin Nyunt won support for the plan from other Southeast Asian leaders, particularly from Thaksin.

But the initiative began to collapse this year. The National League for Democracy boycotted a constitutional convention organized by the government in May, and the government has refused to release Suu Kyi, who has been in detention since the May 2003 attack.

"We regard this as an internal affair of Myanmar, but we would like to see political stability in Myanmar," said Sihasak Phuangketkeow, spokesman for the Thai Foreign Ministry, using the alternative name for the country. A senior Thai government official said, however, there was "a sense of anxiety" at the firing of Khin Nyunt. "We're concerned that perhaps the road map has slowed down in implementation," he said.

In a possible prelude to Khin Nyunt's dismissal, the Burmese foreign minister and deputy foreign minister were fired last month. Both were considered close to the prime minister. They were replaced by military officers allied with Than Shwe.

Tensions between Khin Nyunt and Than Shwe, a career military officer who has headed the junta for more than a decade, had also been building, analysts said.

During the past 18 months, Khin Nyunt had expanded the powers of military intelligence in arrests and investigations and shifted control over foreign trade from local military commanders in key border areas to a border security group that he controlled, said Paul Quaglia, director of Bangkok-based PSA Asia Ltd., a security consulting firm.

The consolidation of power and wealth angered Than Shwe, Quaglia said.

Soe Win, the new prime minister, is among a younger generation of "hard-liners," according to Debbie Stothard, coordinator of Altsean-Burma, a human rights group based in Bangkok. Last year, Soe Win publicly stated that the military junta would not conduct a dialogue or hand over power to Suu Kyi's party, which won more than 80 percent of parliamentary seats in 1990 elections that were voided by the military.

Stothard said that although Khin Nyunt was often cast as a relative moderate, as head of military intelligence, he was responsible for mass detentions and torture. "So we have to be cautious about reinventing him as a reformist progressive," she said.

Gen. Khin Nyunt, the ousted prime minister, had led cease-fire talks with insurgents. He was arrested and charged with corruption.