YANGON (Reuters) - Myanmar's pro-democracy leader Aung San Suu Kyi won a seat in parliament on Sunday, her party said, after an historic by-election that is testing the country's nascent reform credentials and could persuade the West to end sanctions.
Suu Kyi's National League for Democracy (NLD) party claimed victories in at least 19 of the 45 available seats and announced to loud cheers that the Nobel Peace Prize laureate had won in Kawhmu, southwest of the commercial capital Yangon, raising the prospect of a sizable political role following a two-decade struggle against military dictatorship.
The charismatic and wildly popular Suu Kyi, who suffered from illness and exhaustion on the campaign trail, did not address the crowd but issued a statement asking supporters to respect the other parties.
"It is natural that the NLD members and their supporters are joyous at this point," Suu Kyi said. "However, it is necessary to avoid manners and actions that will make the other parties and members upset. It is very important that NLD members take special care that the success of the people is a dignified one."
Traffic around the NLD's crumbling Yangon offices ground to a halt as about 2,000 supporters gathered, waving flags and cheering as one by one, NLD candidates claimed victories.
"We keep hearing we have had more success but we need to hear it from our candidates," a party official told Reuters.
The Election Commission had yet to confirm any of the results and officials from the ruling Union Solidarity and Development Party (USDP) could not be reached for comment.
The United States and the European Union have hinted that they may lift some sanctions - imposed over the past two decades in response to human rights abuses - if the election is free and fair, unleashing a wave of investment in the impoverished but resource-rich country bordering rising powers India and China.
Suu Kyi had complained last week of "irregularities", though none were significant enough for any immediate dispute.
Voters filed into makeshift polling stations from dawn, some gushing with excitement after casting ballots for the frail Suu Kyi, or "Aunty Suu" as she is affectionately known.
Among supporters who voted in her rustic constituency of bamboo-thatched homes in Kawhmu, there was little doubt she would win. "Almost everyone we asked voted for Aunty Suu," said Ko Myint Aung, a 27-year-old shop owner.
To be regarded as credible, the vote needs the blessing of Suu Kyi, who was freed from house arrest in November 2010, six days after a widely criticized general election that paved the way for the end of 49 years of direct army rule and the opening of a parliament stacked with retired or serving military.
President Thein Sein, a general in the former military junta, has surprised the world with the most dramatic political reforms since the military took power in a 1962 coup in the former British colony then known as Burma.
In just one year, the government has freed hundreds of political prisoners, held peace talks with ethnic rebels, relaxed strict media censorship, allowed trade unions, and showed signs of pulling back from the powerful economic and political orbit of its giant neighbor China.
It was rewarded last November when Hillary Clinton made the first visit to the country by a U.S. secretary of state since 1955. Business executives, mostly from Asia but many from Europe, have swarmed to Yangon in recent weeks to hunt for investment opportunities in the country of 60 million people, one of the last frontier markets in Asia.
A small number of officials from Western countries and the Association of South East Asian Nations (ASEAN) were invited to attend the polls but given only a few days to prepare. They called themselves "visitors" rather than observers.
"Whatever irregularities we saw ... did not seem to be out of bad will or intentions. It was more lack of experience or knowledge," said EU delegate Malgorzata Wasilewska, adding that irregularities could still occur in the counting process.
The 2010 election was condemned as rigged to favor the USDP, a party formed by the junta before it ceded power a year ago. The USDP is by far the biggest party in the legislature.
The NLD boycotted that vote. But just as Myanmar is changing, so too is Suu Kyi. Many see her now, at 66, as more politically astute, more realistic and ready to compromise. She has described Thein Sein as "honest" and "sincere" and accepted his appeal for the NLD to take part.
Her top priorities, she says, are introducing the rule of law, ending long-simmering ethnic insurgencies and amending the 2008 constitution that ensures the military retains a political stake and its strong influence over the country.
Many expect Suu Kyi to exert considerable influence and some wonder if conservatives would dare oppose her ideas in parliament given her popularity, especially ahead of a general election in 2015. Many MPs want to be seen aligned with her, basking in her popular support.
The election has not gone smoothly. Suu Kyi has suffered sickness and accused rivals of vandalizing NLD posters, padding electoral registers and "many, many cases of intimidation."
Some of these infractions, however, are quite minor compared with elections elsewhere in Southeast Asia, where vote-buying and even assassinations are common.
On Friday the NLD said a betel nut had been catapulted at one of its candidates and a haystack set on fire close to where another was due to give a speech. It made fresh claims of irregularities on Sunday, alleging coercion by the USDP and damage of ballot papers.
Some critics say Suu Kyi is working too closely with a government stacked with the same former generals who persecuted dissidents, and fear she is being exploited to persuade the West to end sanctions and make the legislature appear effective. Others have almost impossibly high hopes for her to accelerate reforms once she enters parliament.
"Too many expectations are dangerous," says Ko Ko Gyi, a former political prisoner. "She is not a magician."
Some U.S. restrictions such as visa bans and asset freezes could be lifted quickly if the election goes smoothly, diplomats say, while the EU may end its ban on investment in timber and the mining of gemstones and metals.
But some critics say sanctions should remain in place to encourage more reforms and ensure all political prisoners are freed and bloody conflicts with ethnic militias cease.
"Giving the NLD the ability to win an extremely limited number of seats in parliament is not enough," said Joe Crowley, who in January made the first visit to Myanmar by a U.S. congressman in 12 years. "Now is not the time for the international community to rush toward lifting pressure on Burma."
Additional reporting by Paul Eckert in Washington; Writing by Martin Petty; Editing by Tim Pearce