At least 76 people have been injured in Madrid as clashes flared up between protesters and police, the latter using rubber bullets.
Thousands of Spaniards turned out against new cuts introduced by the government.
Those injured include 33 police officers and 43 protesters – miners and their supporters.
Minor arrests have been made so far, with seven people being detained. Three of those arrested reportedly threw bricks at police, local El Pais newspaper reported. Protesters panicked and sought shelter as police began to disperse the crowd, Olvidio Gonzalez, 67, a retired miner from the northern Asturias region told AP.
“We were walking peacefully to get to where the union leaders were speaking and they started to fire indiscriminately. There was no warning,” said Gonzalez, who was also struck by a rubber bullet.
About 200 people remain surrounded by dozens of police in front of parliament, Twitter user Danips posted on his microblog. Some media reports suggest a spontaneous demonstration flared up in front of parliament. Protesters are calling on Spaniards via Twitter to join bigger protests at 19:30 local time.
Protesters disagree with a 63 per cent cut in subsidies to coal mining companies, major contributors to the Spanish energy market. Unions say the plan threatens 30,000 jobs and could destroy their livelihoods.
Miners, who were hiking from the north of the country for the past two weeks, have been joined by tens of thousands of Spaniards also protesting against Prime Minister Mariano Rajoy’s tax hike.
The prime minister announced his decision to raise VAT by 3 per cent as part of the plan to trim the public budget by 65 billion euro over the next two-and-a-half years. Rajoy also declared a 3.5-billion-euro cut to local government spending.
Many protesters marched more than 400 kilometers (250 miles) from mines in northern Spain.