A Thai anti-government protest leader was shot and killed in Bangkok on Sunday when violence erupted as demonstrators blocked early voting in many areas of the capital ahead of a disputed election next week.

It brought the death toll to 10, with scores wounded, since protesters took to the streets in November, vowing to shut down the capital and force Prime Minister Yingluck Shinawatra from office.

'Suthin was shot in the head and in the chest.'- Piya Utayo, National Police spokesperson

A spokesman for the national police, Piya Utayo, identified the dead man as Suthin Tharatin, one of the protest leaders. "Suthin was shot in the head and in the chest," he said.

Yingluck called the Feb. 2 election, hoping to cement her hold on power, but the protests have continued and the Election Commission has been pushing to delay the vote.

Setback for Yingluck

In a clear setback for Yingluck, a senior government official said that as many as 45 of the 50 polling stations set up in Bangkok for advanced voting had been shut because of anti-government protesters.

Bangkok police said clashes had broken out between anti-government protesters and Yingluck supporters, with the two sides trading punches before shots were fired. The Erawan Medical Center, which monitors Bangkok hospitals, said 11 people were hurt in the clashes in the Bang Na district.

It was not immediately clear who had fired the shots, but the protesters accused the government and police of trying to intimidate them.

'The government has allowed thugs to use weapons.'- Akanat Promphan, protester's spokesman

"The government has allowed thugs to use weapons," Akanat Promphan, a spokesman for the protesters, told reporters. Private gun ownership is widespread in the country.

The violence, the worst in a month, came after a state of emergency took effect on Wednesday and adds to doubts over whether the Feb. 2 election can go ahead.

The U.S. State Department said on Sunday it was "deeply troubled by efforts to block polls and otherwise prevent voting in Thailand, and by the most recent acts of political violence.

Not taking sides

"While we do not take sides in the political dispute and strongly support freedom of expression and the right to peaceful protest, preventing citizens from voting violates their universal rights and is inconsistent with democratic values," State Department spokeswoman Jen Psaki said in a statement.

Thailand Politics

Thai Prime Minister Yingluck Shinawatra Yingluck's family is the focus of much animosity. Protesters say she is a puppet of her billionaire brother Thaksin Shinawatra, who was ousted as PM in a 2006 coup. (Apichart Weerawong/Associated Press)

Chris Baker, a historian and Bangkok-based analyst, said the violence added pressure on Yingluck to delay the vote.

"It does weaken the government's position. The protesters will blame this on the government," said Baker. "With or without this incident, the likelihood for violence was there already. I don't think it changes in the trajectory."

The protests are the latest eruption in a political conflict that has gripped Thailand for eight years and is starting to hurt growth and investor confidence in Southeast Asia's second-largest economy.

The conflict broadly pits Bangkok's middle class and elite, and followers in the south, against mainly poor rural backers of Yingluck and her brother, ousted former premier Thaksin Shinawatra, in the populous north and northeast.

THAILAND-PROTEST/VOTE

Officials look at a masked anti-government protester entering a polling station his group forced to close in Bangkok on Sunday. (Damir Sagolj/Reuters)

The protests mark the biggest demonstrations since deadly political unrest in April and May 2010, when Thaksin's "red-shirt" supporters paralysed Bangkok to remove a government led by the Democrat Party, now in opposition. More than 90 people were killed and more than 2,000 injured in that unrest.

Yingluck, who would probably win the election easily, is set to meet Election Commission officials on Tuesday. The Democrat Party also plans to boycott the election.

The protesters, led by firebrand former deputy premier Suthep Thaugsuban, accuse Yingluck of being Thaksin's puppet and want an unelected 'people's council" to oversee reform before any future election is held.