BRASILIA (Reuters) - The Brazilian government on Wednesday agreed to lower the minimum retirement age for police officers in a pension reform, a day after members of their unions stormed Congress to protest the controversial bill aimed reining in soaring public debt.

Striking police officers set fire to coffins during a protest by Police officers from several Brazilian states against pension reforms proposed by Brazil's president Michel Temer, in Brasilia, Brazil. REUTERS/Adriano Machado

Congressman Arthur Maia, a government ally sponsoring the bill, reduced the minimum retirement age for police to 55 from 60 in his draft of the reform.

Finance Minister Henrique Meirelles called the concession to police unions “symbolic” and said it would have little impact on the fiscal result of the bill. Still, he said he saw little room left for more compromises with interest groups.

“I think we are more or less at the limit of the changes than can be made without substantially altering the country’s fiscal balance,” he told reporters in Washington.

After Maia revealed the details of his original proposal on Tuesday, hundreds of police union members dressed in black shirts broke the windows of the main entrance of the legislature in Brasilia and clashed with congressional guards.

The violent incident, in which the guards used pepper spray and stun grenades to disperse the protesters, highlighted the unpopularity of the reform proposal that is central to President Michel Temer’s austerity agenda.

Labor unions are threatening months of street demonstrations even after Temer has repeatedly watered down the proposal, which would trim some of the world’s most generous pension benefits in order to boost investor confidence in Brazil’s slumping economy.

Meirelles said he still expects the reform to pass by June.

The initial vote on the proposal has been set for May 2 at the commission. As a constitutional amendment, the measure has to be approved by a three-fifths majority in separate votes by both houses of Congress.

The lower house also voted on Wednesday to fast-track a labor reform that Temer has proposed to make work contracts more flexible and improve Brazil’s business environment.

A similar vote had failed on Tuesday due to what House Speaker Rodrigo Maia called a parliamentary error.