At least 12 people, including nine police, were injured on Wednesday during a protest rally in Kyrgyz capital, Bishkek, the country’s Health Ministry said.

A crowd of some 500 people gathered in front of a building housing the parliament and government offices in the center of the capital demanding the nationalization of a vital gold mine owned by a foreign company.

The rally turned into violent clashes with police after a group of protesters, headed by opposition leader Kamchibek Tashiyev, attempted to break into the building.

Police used stun grenades, tear gas and dogs to disperse the crowd, while protesters pelted law enforcement officers with rocks.

“At least twelve people required medical treatment after the rally,” the ministry said. “Seven people were hospitalized, including five police officers.”

The ministry denied earlier reports claiming that three people received gunshot wounds as someone in the crowd opened fire at police.

“Emergency services received phone calls from the bystanders reporting gunshot wounds,” ministry spokesperson Yelena Bayalinova said.

“However, the doctors did not find any gunshot wounds after a thorough medical examination of the injured,” she said.

Several rioters were arrested in the wake of the clashes as the crowd left the square and dispersed in small groups in surrounding parks.

The controversial Kumtor gold mine in the east of the country is owned by Toronto-based Centerra Gold.

Although the mine generates over 10 percent of the country’s GDP, it has been the source of a series of toxic spills in past years.