BRASÍLIA -  Brazil’s Senate approved Tuesday a 20-year freeze on government spending billed as a centerpiece of austerity reforms, sparking angry clashes in the capital Brasilia where protesters torched a bus.

Hundreds of people, many with their faces covered, clashed with police who fired tear gas to break up the crowd following the upper house vote, which saw the measures quickly pushed through by 53 votes to 16.

Center-right President Michel Temer says the spending freeze is needed to get Brazil’s finances back under control, but his austerity policies have prompted violent protests and were criticized last week by a UN expert as “a historic mistake.” During the vote, police were out in force to protect government buildings as around 2,000 people turned out for a demonstration in which a bus was burned.  Police said they arrested 100 people.  Union leader Luis Jorge expressed anger that the Senate had managed to rush through the vote “before we could demonstrate.

Protests also erupted in Sao Paulo, where leftwing demonstrators attacked the headquarters of FIESP, the country’s main industrial association, before being driven back.

The vote means that the spending cap is now mandated by the constitution, serving as the central plank in Temer’s bid to “transform” the broken economy, which is in deep recession.

However, Temer is rapidly losing political clout as he and many of his senior allies fight to survive a slew of corruption allegations. With unemployment at nearly 12 percent and stubbornly high inflation, Brazilians are increasingly angry over the scandals and hostile to the austerity measures.

Francisco de Oliveira, a 56-year-old economist from Rio Grande do Norte state who was passing through Brasilia, said that he was in favor of what he called a “necessary” amendment.

But a poll published Tuesday showed that 60 percent of Brazilians oppose the spending ceiling, with only 24 percent in favor, according to a Datafolha poll published in the Folha newspaper.

When the Senate held a first vote on the measure two weeks ago, protesters fought riot police outside Congress, burning cars and smashing windows.

In an attempt to claw back public support, Temer has unveiled stimulus measures that would attempt to give a short-term boost to the ailing economy, the largest in Latin America.

But as the Senate began debating, he defended his far-reaching austerity proposals, saying they were needed to change Brazil for the long term. In addition to the spending ceiling, a separate measure is being submitted to Congress proposing pension reforms.

Central to this would be raising the minimum retirement age to 65, substantially higher than the current level which can be as low as 55 but varies widely between professions.

“We need a lot of courage at this moment in Brazil to do things that are apparently unpopular but which will bring popularity later,” he said in a statement.

“We need to transform the country,” he said.

- ‘A generation at risk’ -

Philip Alston, the UN poverty and human rights rapporteur, attacked the 20-year spending cap as “putting an entire generation at risk of social protection standards well below those currently in place.”

“This is a radical measure, lacking in all nuance and compassion,” he said last week.

“It will hit the poorest and most vulnerable Brazilians the hardest.”

However, Temer won plaudits from US President-elect Donald Trump who congratulated him on the reforms in a phonecall, the Brazilian presidency said.

Temer’s entire government is struggling in the face of allegations tying senior figures and the president himself to the giant embezzlement and bribery probe centered on state oil company Petrobras.

Temer took over in August following the impeachment of leftist president Dilma Rousseff. As her deputy, he took the post automatically for the rest of her term through 2018. He pledged to end the political and economic chaos that doomed the Rousseff government.

But the latest poll from Datafolha shows 63 percent of Brazilians want him to resign to allow early elections, with only 10 percent saying they thought his government was doing a good job.