(Buenos Aires) Argentina’s riot police dispersed protesters using water cannons outside Congress on Wednesday, escalating tensions before lawmakers vote on state reform and tax bills proposed by President Javier Milei.

Libertarian Milei’s political opponents, powerful unions and thousands of protesters began converging on Congress Wednesday morning, when the Senate opened debate on key legislation.

Protesters urged senators to reject Mr. Milei’s agenda of harsh austerity and economic deregulation. Hundreds of police backed by armored vehicles equipped with water cannons blocked the road outside the city square in Buenos Aires, the country’s capital. The demonstrators jostled against the chain of police officers.

The vote is the most serious test yet of the libertarian leader’s vision for governance and change.

Mr. Milei rose to power promising that he would resolve Argentina’s worst economic crisis in two decades. But his fledgling political party holds only a tiny minority of seats in Congress and he has struggled to strike deals with the opposition.

This watered-down version still delegates broad legislative powers to the president over energy, pensions and security, and includes measures to encourage investment, deregulate the economy and reduce the deficit.

Some sensitive issues, such as union takeover of health care and the privatization of Argentina’s national oil company, were abandoned in the hope of reaching a compromise.