Riot police in Argentina's capital Buenos Aires have fired tear gas and water cannon to disperse protesters outside Congress, where lawmakers have been debating budget-slashing reforms, reports BBC.
Demonstrators - who say the measures will hurt millions of Argentines - threw petrol bombs and stones, setting one car alight.
A number of people were reported injured, with local media describing the scene on Wednesday as a "battlefield".
The reform package, proposed by right-wing President Javier Milei to revive the country's flagging economy, includes declaring a state of economic emergency, cutting pensions and watering down labour rights.
The measures are opposed by leftist political parties, labour unions and social organisations.
Scuffles broke out when protesters tried to make their way towards Congress through fences, with demonstrators throwing rocks at officers who pepper sprayed them.
Observers and opposition MPs reportedly said dozens of demonstrators and a handful of MPs received medical attention. At least five opposition MPs in the crowd were hospitalised, legislator Cecilia Moreau told AFP news agency.
Police later pushed back protesters, who reportedly set two vehicles on fire - including that of a news organisation.
"We cannot believe that in Argentina we are discussing a law that will put us back 100 years," Fabio Nunez, a 55-year-old protesting lawyer, was quoted by AFP as saying.
President Milei's office issued a statement thanking the security forces for repressing what it described as "terrorists" attempting to carry out a coup d'état.
The debate on the bill in the Senate is set to continue late into Wednesday, with senators expected to take a vote on it.
The highly-divisive bill was approved by the lower house in April, with significant changes.
If approved in the Senate, it will return to the lower hours for final approval.
Mr Milei came to office in 2023 after vowing to take a chainsaw to public spending.
While on the campaign trail, he even brandished a chainsaw while making a speech to symbolise his determination to do so.