Anti-government demonstrators swarmed dozens of polling stations in Thailand on Sunday to stop advance voting for next week's general elections, chaining gates shut, threatening voters and preventing hundreds of thousands of people from casting ballots.

A protest faction leader was fatally shot in a confrontation near a polling center that also left 11 people wounded, and isolated street brawls broke out in several parts of Bangkok.

The chaos underscored the precariousness of Thailand's fragile democracy, and the increasing weakness of Prime Minister Yingluck Shinawatra's elected administration. Yingluck had called the Feb. 2 vote in a failed bid to ease months of street protests, but police did not disperse the crowds because of longstanding orders to avert violence, which many fear would give the all-powerful army reason to stage a coup.

Although most polling stations in Bangkok and many in the opposition stronghold in the south were forced to close, voting proceeded largely unhindered in the rest of the country. Still, the upheaval proved that demonstrators struggling to overthrow Yingluck have the ability to disrupt the main vote next week, and the country's electoral commission is unlikely to stand in their way.

The commission, which agrees with protesters that the poll should be delayed, is legally mandated to ensure registered voters are able to cast ballots safely. But on Sunday, its members “just sat down and watched this thing collapse around them,” said Sunai Phasuk, a senior researcher at Human Rights Watch.

The commission is supposed to be a neutral body, but critics have accused its members of taking sides. Its top executive has posed for at least one smiling photo with demonstrators, and its officials failed to denounce a violent effort by protesters to disrupt candidate registration in December.

Similarly on Sunday, the commission issued no public condemnation of attempts to derail voting. Sunai said members did not call on security forces to defend the ballot.

Analysts say that is because courts and the country's independent oversight agencies are largely aligned against the current government in collusion with the army, royalists and powerful businessmen. Yingluck is facing several legal cases that could end with her or her party being banished from governing because of alleged corruption or violations of the constitution.

Suthida Sungkhapunthu, a 28-year-old office worker, said she turned back from one polling station after reading news of the day's mayhem on her phone.

“I saw this coming but I'm still quite disappointed,” she said, calling the protesters “undemocratic” as she watched a mob surrounding her polling station a block away. “It's my constitutional right” to vote, she said.

The protest movement, known as the People's Democratic Reform Committee, had pledged not to obstruct the poll, saying its supporters would only stand outside to express their views and urge people not to vote. Protest spokesman Akanat Promphan told The Associated Press that those who had locked the gates of polling stations had “acted on their own,” but he did not criticize them and said the decision to close stations was made by Election Commission officials.

The protesters' effort, however, appeared to have been widely coordinated. Across Bangkok, demonstrators waving the Thai flag physically blocked electoral officials, ballot boxes and voters from getting inside polling centers. Some did vote, but officials ultimately shut 48 of the city's 50 voting stations. Eleven more shut in the south, bringing the total number closed to 59 out of 152 nationwide, authorities said.

Scuffles broke out in some areas, and Bangkok's emergency medical center said at least one person was killed and 11 wounded in a clash near a polling station in southeast Bangkok. The slain man was Sutin Tharatin, a protest faction leader who was shot in the head by political rivals, according to police.

Sunai said some protesters had threatened and intimidated would-be voters, and in at least one case had attempted to strangle a man.

“You cannot call this peaceful,” he said. “It's a sad day for democracy when the right to vote, which is a basic requisite, is assaulted by a political movement that claims to be striving for reform and people's empowerment. Everything that happened today shows they are striving for the opposite.”

International Federation for Human Rights president Karim Lahidji also said protesters had gone too far.

“Blocking citizens from exercising their voting rights is a serious violation of Thai laws and international human rights standards,” he said. “The right to peaceful assembly must not infringe on the citizens' fundamental right to vote.”

The protesters are demanding Yingluck's government be replaced by a non-elected “people's council” that would implement anti-corruption reforms before elections. They accuse her of corruption and allege the ruling party has employed its electoral majority to subvert democracy.

Much of their hatred is directed at Yingluck's family. They say she is a puppet of her billionaire brother Thaksin Shinawatra, an exiled former premier they allege used the family fortune and state funds to influence voters. Thaksin was ousted in a 2006 coup that provoked a struggle between that in broad terms pits Thailand's rural north against an urban elite backed by royalists and the  south.

About 49 million of the nation's 64 million people are eligible to cast ballots in February, and 2.16 million applied for early voting. But even before Sunday, there had been increasing doubt that the Feb. 2 poll would go ahead.

Even if it does, Parliament is unlikely to achieve the quorum it needs to convene, which would prevent a new government from being formed.

Ruling party officials suggested over the weekend that they were willing to delay next week's ballot, but only if protests end and the main opposition party abandons its boycott. There has been no sign yet that Yingluck's rivals would agree to any deal, however. (AP)