At least 10 people have been killed as striking oil workers clashed with government forces in a town in western Kazakhstan, officials say.Eyewitnesses said police fired on the protesters in the town of Zhanaozen, but the authorities deny this.The clashes occurred when police tried to clear the town\'s main square, occupied by the oil workers for more than six months.They are demanding better pay, but their action has been declared illegal.The clashes came as Kazakhstan marked the 20th anniversary of independence from the Soviet Union, with celebrations throughout the country.Police moved in to clear the square early on Friday morning for the celebrations but were charged by the oil workers.Eyewitnesses told the BBC that several people were killed and injured, and a number of buildings including local government offices, a hotel and the office of the state oil company were set on fire.Kazakhstan\'s general prosecutor said later that preliminary information indicated 10 deaths, with police officers among the injured.Some yurts and a portable stage erected for Independence Day were destroyed, the prosecutor said.He added that a criminal investigation had been opened into the disturbances, which had resulted from \"criminal actions\".Oil workers at the Ozenmunaigas oil field have higher than average salaries, but strike organisers say the workers are owed danger money for the tough conditions they work in.The oil-rich but remote western Mangistau region has seen several cases of industrial action this year, with oil fields responding by sacking hundreds of workers.