At least 10 people were killed Friday in violent clashes between police and demonstrators in an oil town in western Kazakhstan where workers have been protesting for higher wages, authorities said.
Prosecutor General Askhat Daulbayev said in a statement that the mayor's office, a hotel and vehicles were set afire in Zhanaozen, a city of 90,000 in the far southwestern corner of the energy-rich Central Asian nation.
The clashes appear to be some of the largest unrest to hit the former Soviet republic since it gained independence in 1991.
Contradictory accounts have emerged as to what precipitated the confrontation.
Daulbayev said police officers were attacked as they sought to quell a disturbance in the city center and were forced to fire their weapons on protesters. He said 10 people were killed.
Roza Teletayeva, who said she was a former oil worker dismissed in June for taking part in a long-standing strike, told The Associated Press that a peaceful meeting of several hundred demonstrators was surrounded by police in the morning.
"We had no idea what was going to happen, we were just standing peacefully and doing nothing," she said.
Teletayeva said police opened fire on the crowd and that she personally had seen at least five people who had been killed. Teletayeva said groups of angry young men later marched on the mayor's office and set it ablaze. Footage broadcast by satellite channel K+ showed men in worker's outfits charging a stage erected for festivities to mark the 20th anniversary of Kazakhstan's independence Friday.
Daulbayev said the headquarters of OzenMunaiGaz oil company, where the demonstrators were formerly employed, was also set alight.
A team of Interior Ministry investigators has flown to the town to identify and punish the organizers of the unrest and restore order, Daulbayev said.
Hundreds of workers at an oil facility controlled by the state-owned energy company KazMunaiGas in Zhanaozen have been protesting for better salaries and working conditions for more than six months. Almost 1,000 workers were fired in the summer for striking, but demonstrations have continued.
President Nursultan Nazarbayev has kept a tight lid on any signs of public discontent during his 20 years of rule. The apparent scale of unrest in Zhanaozen will come as a shock to Nazarbayev's government, which has also been combating an unprecedented surge in radical Islamist-inspired violence in recent months.
In a sign that Kazakhstan's authoritarian government were attempting to contain information on developments in Zhanaozen, Internet users reported being unable to open independent news websites or Twitter.
Virtually all domestic media failed to cover the events throughout Friday as lavish celebrations were taking place in the capital, Astana, several hundred kilometers (miles) away to mark the independence anniversary.