WARSAW, Poland (Reuters) -- Polish coal miners have attacked riot police with sticks, burning boots and chunks of road stone as a protest against planned job cuts and pit closures turned into one of the country's worst riots in years.

Miners marching in central Warsaw on Thursday lit petrol-soaked work boots and clothes and hurled them at police in riot gear defending a government ministry. One officer's uniform caught fire and at least three were injured, police said.

Police fired into an unruly crowd of about 5,000 miners with tear gas, water cannon and rubber bullets, as trade union organizers lost control of what had been planned as a peaceful demonstration on Thursday. There were no details of arrests.

"We are desperate and have nothing to lose. If they sack us we have no place to go -- and I have two kids and a wife to look after," said Piotr Wesoly, 44, who has worked a Silesian pit for 26 years.

The government has run into bitter resistance from workers opposed to plans to close four out of Poland's 23 pits to reduce excess capacity. Around 14,000 job cuts are planned -- or 10 percent of the coal industry workforce.

The unpopular left-wing government faces an uphill struggle to reform loss-making state industries before Poland next year joins the European Union, which demands newcomers restrict state aid to industry.

"In Poland you can't do anything without force and this is only the beginning," said 42-year-old miner Tadeusz, who would not give his last name.

Coal was a prestige industry under communism, and well-organized miners are still among the best paid industrial workers in the eastern European country of nearly 40 million.

Successive restructuring efforts, backed by World Bank loans, have reduced employment from a peak of 300,000, but at the expense of a rise in unemployment in southern industrial Silesia to 16 percent -- still below the national average.

The miners changed their planned route to pass the United States embassy, but did not prevent Prime Minister Leszek Miller from attending a memorial event to mark the second anniversary of the September 11 attacks.