efe-epaBuenos Aires

Chaos erupted on Monday outside the Argentine Congress in a clash between violent protesters and police and later resurged, leaving at least 81 people injured and 48 under arrest, while in the Chamber of Deputies opposition lawmakers asked the government to cancel the session to debate the controversial pension reform being pushed by the administration of Mauricio Macri.

By 6 pm, the violence had left at least 48 police officers injured with eye and head wounds, along with multiple other injuries, and they were transported to local hospitals, officials with the city's Justice and Security Ministry said.

In addition, at least 33 civilians were taken to several hospitals.

The situation got out of hand to the point where, although Buenos Aires police were initially on hand, ultimately authorities decided to call in the Federal Police and the Gendarmeria, a militarized police unit.

Before the start of the legislative session, about 2 pm, the demonstrators, called out by social and union organizations, began to confront police by hurling stones and bottles at them.

However, later the protesters began setting fire to assorted objects, setting off firecrackers and crowding around the barrier that surrounds Congress.

That was when police began firing rubber bullets into the crowd and using pepper spray.

The disturbances came after last Thursday, when the reform was to be debated in another lower house session, protesters clashed with police, leaving dozens injured and several people under arrest.

"We ask you to think about this. It's a ... very serious situation. We've made the decision to hold this session as a way to avoid violence in Argentina," opposition lawmaker Augustin Rossi, with the Kirchnerist Front for Victory, said during Monday's session.

The Macri government claims that the disturbances are being fostered by the opposition to block legislative debate on the measure.

Meanwhile, Argentina's largest workers' union, the Confederacion General del Trabajo (CGT), called a 24-hour strike Monday to reject the controversial reform of the pension system that the government was trying to pass in the lower house of Congress.

"It signifies a cut in income for retirees, pensioners and the most vulnerable sectors of society," Juan Carlos Schmid, one of the union's three secretary generals, told a press conference where he announced that the walkout would begin at noon and continue into Tuesday.

So that workers can return home and join in the march around Congress to protest against the reform, the strike of transport services will not get fully under way until midnight this Monday.

In other sectors, activities will be progressively paralyzed throughout the day to show the "absolute rejection" of a bill promoted by the Macri government and which has already been approved by the Senate.

According to Schmid, the CGT rejects it because the union did not participate in its preparation nor in any debate about it, and above all, because its members cannot agree with any of its proposals.

So that legislators stop accusing the union of doing nothing but protesting, he asked the president and the legislature to have the "common sense" to call a popular referendum to "see if Argentine society agrees with the imposition of an adjustment like this."

The lower house session where the reform was to be debated last Thursday had to be suspended due to the outburst of insults and aggression among lawmakers, a scene repeated with even more violence in the surrounding streets, where there were heavy and violent clashes between demonstrators and security forces, which repressed the crowds and arrested several protesters.