A number of mysterious bomb blasts have unsettled this usually somnolent country, rocking a public monument, a luxury hotel, an outdoor market and the international airport. Rebels loyal to the deposed monarchy have stepped up their activities, crossing the border from Thailand to attack a customs post. And Hmong tribesmen, who once fought in a CIA-backed army, have ventured out of mountain hideouts to stage fierce raids on government forces.

A quarter-century after Marxist guerrillas seized power here, defeating a U.S.-supported government and establishing one of the world's few remaining communist regimes, tiny Laos is in the throes of an enigmatic political crisis. The opaque government, run by an aging, eight-member Politburo, has offered few details on the turmoil. Foreign diplomats and academics have varying but inconclusive explanations, but they agree the explosions are part of an unprecedented protest against leaders who have steadfastly refused to embrace economic and political reform.

"The Berlin Wall fell. The whole Soviet Bloc split apart. People here thought it was only a matter of time until things changed," said a Western businessman who has lived here for several years. "There's an incredible feeling of frustration" among the Laotian people."

Twenty-five years ago this month, Laos became the third Southeast Asian domino to fall to Communist forces, after Vietnam and Cambodia. Today, though, Vietnam is gradually opening to the outside world to promote economic development. Cambodia, after rule by a genocidal regime and a Vietnamese military occupation, now seems to be on a path toward political stability and global engagement. But Laos--surrounded by China, Vietnam, Burma, Thailand and Cambodia--remains one of the world's most reclusive and undeveloped countries, still run by many of the Pathet Lao guerrillas who fought in the jungles against U.S.-sponsored forces.

Western movies and magazines are officially banned here. The bulk of the population live in the mountainous countryside, where they have no access to telephones or electricity. With most people engaged in subsistence farming, development specialists place Laos among the world's 10 poorest nations.

The country also bears the scars of the Vietnam War. Secret U.S. efforts to stop Vietnamese forces from crossing through Laos along the Ho Chi Minh Trail resulted in the dropping of so many on the country that Laos became, on a per capita basis, the most heavily bombed nation in history. Derelict U.S. bombs continue to kill and maim scores of people each year, most of them children who treat some explosive devices as toys.

Nowadays, however, a small but growing segment of the population in Vientiane and along the Thai border is getting a glimpse of the outside world. People in these regions can tune in to Thai television, and some have been visiting Internet cafes set up for foreign backpackers. Some analysts believe that taste of globalization, coupled with lingering frustrations among opposition groups, is giving rise to a backlash against the Communist Party.

Last year, for the first time in decades, a group of about 50 university students and teachers attempted to stage a demonstration calling for democratic rule. It was quickly broken up by security forces, and several participants were arrested. But the protest has led to copycat events. Last month, for instance, about 200 workers and students were reported to have organized a democracy demonstration in a southern province.

"The bombs could be a form of protest," said a Western diplomat in Vientiane. "They could be doing this because there's no legal way to get your voice heard here."

Many believe the calls for democratic reform are being fueled by an economic squeeze. Although Laos remains one of world's least globalized economies, it nevertheless was hurt by the recent Asian financial crisis. The value of the Laotian currency fell by more than 900 percent against the U.S. dollar last year, while inflation surged to 150 percent. All of a sudden, teachers, soldiers and government workers found their paychecks essentially worthless.

The currency has since stabilized, but fundamental problems persist. Inflation still is running at about 30 percent, and some international donors have threatened to pull out if the government does not speed up free-market reforms.

"The people are not happy here anymore," said a university professor in Vientiane who, like other Laotians interviewed for this article, did not want his name published because he fears government retribution. "They can see the prosperity in Thailand--and even in Vietnam. But here, they can't get a good job."

The professor said he believes the bombings stem from the fact there is no open debate about how to cure the nation's economic ills. "We have only one party here," he said. "You cannot criticize them. You cannot discuss policy."

Unlike neighboring Burma, where Nobel Peace laureate Aung San Suu Kyi has led a determined opposition to an authoritarian military government, no charismatic democratic leader has yet emerged in Laos.

Another scenario ascribed to by some analysts and diplomats is that the bombings are the work of a faction within the ruling party seeking to discredit those in charge before a party congress scheduled for the spring. Although party leaders are divided by age and geography, political observers say the most plausible split is between veteran leaders who are loyal to Vietnam, including the president and the prime minister, and a younger group, including the foreign minister, advocating closer ties with China.

At least two of the bombings were aimed at Vietnamese targets in Vientiane, including a Vietnamese-owned shop at the central market and the homes of Vietnamese workers. Another explosion occurred in the ruling group's southern heartland.

Although Vietnam provided crucial support for the Communists during their fight to topple the government and in the austere postwar years, China has recently begun to court Laos as aggressively as--if not more than-- Vietnam. Beijing has provided export subsidies and interest-free loans to stabilize the currency. And China recently donated millions of dollars to build an imposing, four-story cultural center in the middle of Vientiane.

"It's clear that China has been making moves to increase its influence in Laos," said a Western diplomat in Vientiane. The diplomat and others believe President Khamtay Siphandon and Prime Minister Sisavat Keobounphan, who are dependent on Vietnamese support, may be quietly discouraging closer ties with Beijing, which has raised the ire of the pro-China faction.

Other splits also appear to be emerging within the leadership. Khamsay Souphanouvong, a former finance minister who is the son of the country's first president, recently fled the country and applied for political asylum in New Zealand. Some analysts believe he had a falling out with members of the ruling clique, although the government has said he is simply studying English.

Others, however, suggest that the bombings may be the work of the Hmong or supporters of the former king, who died in a Communist reeducation camp. Both groups have long carried on a low-grade resistance to the government, largely funded and directed by members who fled to the United States and other countries. Either group, say analysts, may be seeking to send a message timed to this month's 25th anniversary of the Communist takeover and the upcoming party congress.

But many diplomats and analysts doubt the Hmong or royalists are to blame for the bombings, because neither group has active rebel networks in Vientiane. It is more likely, they say, that the two groups have decided to capitalize on the turmoil and uncertainty to increase their own activities.

The 60 rebels who mounted the attack on the border post had a document linking them to Crown Prince Soulivong Savang, who fled after the Communist victory. He now lives in France and has been actively lobbying in the United States and Europe against the government.

The Hmong, an ethnic minority whose members fought as mercenaries for the CIA against Vietnamese and Communist Laotian forces in the 1960s and 1970s, still operate in the mountains of northern Laos. Although the government has tried to eliminate the rebel movement, security forces have never been able to contain them.

In the past year, diplomats said, the Hmong rebels have been mounting bold attacks on government military positions. Analysts familiar with the Laotian army said the ferocity of the assaults has resulted in an increased Vietnamese military presence within Laos. The analysts believe as many as 10,000 Vietnamese soldiers may still be in Laos.

The bombings and the increased resistance activity have heightened tensions across the country and particularly in Vientiane, a dusty city on the Mekong River. Officials have imposed a nighttime curfew in the city, and many restaurants, bars and hotels now have uniformed security guards.

The government has said nothing to reassure people here. The latest blast occurred near one of the city's monuments on the eve of a meeting among Southeast Asian foreign ministers and European diplomats. The government initially said it resulted from an aerosol can dumped in a trash fire. Later, the Laotian foreign minister said the blast was caused by a leftover American bomb--even though none were dropped over Vientiane.