Supporters of a presidential hopeful who was not allowed to register as a candidate stormed government headquarters Friday and clashed with police. Thirty-nine people were injured in Kyrgyzstan's largest disturbance since the March uprising that ousted the leader of the former Soviet republic.

Police and Interior Ministry troops firing tear gas regained control of the building an hour after about 2,000 people forced their way through a gate. As many as 100 troops carrying riot shields and truncheons sealed off the building after driving out protesters. They then advanced on the crowd outside, beating their shields and causing protesters to break and run.

The Health Ministry said 39 people were injured, 12 of them hospitalized. Interim President Kurmanbek Bakiyev said 10 security troops were injured by stones.

The protesters said they were supporters of Urmat Baryktabasov, a candidate who was prevented from registering in next month's presidential election in Kyrgyzstan on the grounds that he is a citizen of Kazakhstan. A spokeswoman for Baryktabasov's political party, Bermet Turduniyazova, told the Associated Press that neither the candidate nor the party was involved in the storming.

Bakiyev, the interim president, blamed backers of former president Askar Akayev.

The July 10 election was called to replace Akayev. Seven candidates have been registered, including Bakiyev, who is the front-runner.

Farida Mambetakunova, 35, from Baryktabasov's home region of Ysyk-Kol in northeastern Kyrgyzstan, on the border with Kazakhstan, vowed to fight on. "Our goal is to elect him as our president. We will wait here until he is given a mandate to run in the race. We won't leave until then," she said.

"He gave us jobs and money," she said. "Bakiyev hasn't done anything since coming to power."

The Organization for Security and Cooperation in Europe, which is monitoring the campaign, called on all sides in Kyrgyzstan to respect the rule of law. "The OSCE expects all political forces in Kyrgyzstan only to use peaceful means to solve any election-related disagreements," said Ayhan Evrensel, a spokesman for the organization.

The election "is crucial for Kyrgyzstan to have stable democratic development. Questions regarding Central Election Commission decisions on candidates' eligibility should be addressed in the courts," Evrensel said.

Violence broke out Monday in the southern city of Osh when security guards opened fire on traders demanding fair prices. Seven people were injured, two seriously.

Last week, a lawmaker who owned the biggest car market in Bishkek, the Kyrgyz capital, was shot and killed. Authorities on Tuesday announced a $25,000 reward for information to help solve the case.