YANGON, Myanmar (AP) — Myanmar election officials confirmed Monday that Aung San Suu Kyi’s opposition party had won a landslide victory in historic by-elections, with the democracy icon saying she hopes the vote marks the beginning of a new era for the long-repressed country.
Before the official announcement, Suu Kyi spoke to thousands of cheering supporters who gathered outside her party’s headquarters a day after the party declared she had won a parliamentary seat in Sunday’s closely watched vote.
‘‘The success we are having is the success of the people,’’ Suu Kyi said, as a sea of supporters chanted her name and thrust their hands into the air to flash ‘‘V’’ for victory signs.
Later, the state election commission confirmed that her National League for Democracy party had swept to a victory that will put it at the head of a small opposition bloc in the military-dominated parliament.
State radio and television reported the commission’s announcement that the NLD had won 40 of the 45 seats at stake. Results from five constituencies in remote areas were not yet reported.
The NLD’s own count gave it 43 seats, while it awaited results from one constituency in distant Shan State. It failed to contest one constituency after its candidate was disqualified.
‘‘It is not so much our triumph as a triumph of the people who have decided that they have to be involved in the political process in this country,’’ Suu Kyi said. ‘‘We hope this will be the beginning of a new era.’’
The Nobel Peace laureate will take public office for the first time and lead the small bloc of lawmakers from the NLD in parliament, where it will hold just about 6 percent of the seats.
The victory marks a major milestone in the Southeast Asian nation, which is emerging from a ruthless era of military rule, and also an astonishing reversal of fortune for a woman who became one of the world’s most prominent prisoners of conscience.
Nay Zin Latt, an adviser to President Thein Sein, told The Associated Press that he was ‘‘not really surprised that the NLD had won a majority of seats’’ in the by-election. Asked if Suu might be given a Cabinet post, he said: ‘‘Everything is possible. She could be given any position of responsibility because of her capacity.’’
Unofficial counts continued to trickle in Monday from poll watchers within Suu Kyi’s party, and spokesman Han Than said the opposition had won at least 43 of the 44 parliament seats it had contested. Those included all four seats up for grabs in the capital, Naypyitaw, which is populated by civil servants and would be an embarrassing sign of defeat for the government.
An official from the Election Commission said its regional office for the main city of Yangon had confirmed that Suu Kyi’s party had won all six constituencies contested there and that full results from remote areas were expected by midweek. The official spoke on condition of anonymity because he was not allowed to speak to the media.
The former junta had kept Suu Kyi imprisoned in her lakeside home for the better part of two decades. When she was finally released in late 2010, just after a general election that was deemed by most as neither free nor fair, few could have imagined she would so quickly make the leap from democracy advocate to elected official — a victory her supporters hope will open the way for a potential presidential run in 2015.
But Myanmar has changed dramatically over that time. The junta finally ceded power last year, and although many of its leaders merely swapped their military uniforms for civilian suits, they went on to stun even their staunchest critics by releasing political prisoners, signing cease-fires with rebels, relaxing press censorship and opening a direct dialogue with Suu Kyi, who was awarded the Nobel Peace Prize in 1991 while under house arrest.
Hoping to convince the international community of its progress, Myanmar invited dozens of Western and Asian election observers to monitor the vote and granted visas to hundreds of foreign journalists.
Suu Kyi herself said Friday that campaigning had been marred by irregularities and could not be considered fair — allegations her party reiterated Sunday.
Malgorzata Wasilewska, head of the European Union’s observer team, called the voting process ‘‘convincing enough’’ but stopped short of declaring it credible yet. ‘‘In the polling stations that I visited ... I saw plenty of good practice and good will, which is very important,’’ she said.
The United States and the European Union have said that the fairness of the voting will be a major factor in their decision on whether to lift economic sanctions that were imposed to penalize the former junta.
U.S. Secretary of State Hillary Rodham Clinton congratulated Myanmar for holding the poll. Speaking at a news conference in Istanbul, Turkey, she said Washington was committed to supporting the country’s reform effort.
‘‘Even the most repressive regimes can reform, and even the most closed societies can open,’’ she said.
The topdown revolution has left Myanmar befuddled and wondering how it happened — or at least, why now? One theory says the military-backed regime had long been desperate for legitimacy and a lifting of Western sanctions, and its leadership had quietly recognized that their impoverished country, formerly known as Burma, had fallen far behind the rest of skyscraper-rich Asia.
Sunday’s by-election was called to fill 45 vacant seats in Myanmar’s 664-member bicameral assembly and regional parliaments, and the military-backed government had little to lose by holding it. The last vote had already been engineered in their favor — the army was allotted 25 percent of the seats, and the ruling party won most of the rest.
David Scott Mathieson, an expert on Myanmar for Human Rights Watch, said ‘‘the real danger of the by-elections is the overblown expectations many in the West have cast on them.’’
‘‘The hard work really does start afterward,’’ he said. ‘‘Constitutional reform, legal reform, tackling systemic corruption, sustainable economic development, continued human rights challenges ... will take many years.’’