Caracas – Amid tensions and violent clashes between pro- and anti-government protesters, the opposition-dominated Venezuelan National Assembly kicked off measures to impeach the judges of the Supreme Court, that backs President Nicolas Maduro.

The opposition is accusing Supreme Court judges of attempting an internal “coup d’etat” for seeking to take over the opposition-majority legislature’s powers last week.

Last week, the Supreme Court issued rulings transferring the National Assembly’s legislative powers to itself and revoking lawmakers’ immunity from prosecution.It later reversed the rulings after an international outcry, but kept in place other measures limiting the assembly’s powers.

Opposition lawmakers launched an effort to impeach the judges on Wednesday. But that would require a green light from the attorney general, prosecutor general and comptroller, all Maduro allies.

They refused Thursday to give the go-ahead — though the attorney general had sharply criticized the Supreme Court rulings, in a rare display of dissent in Maduro’s camp.

On the streets, protesters said they want to get rid of Maduro.

The opposition said that 50 people were wounded in the clashes between the protesters and police, who used tear gas and water cannons to disperse them. Similar rallies took place on Tuesday in Caracas.

On Wednesday, clashes broke out in the western city of San Cristobal, the scene of deadly riots and looting last year, and in the city of Valencia.

The wave of protests has revived fears of broader unrest in Venezuela, where 43 people were killed during riots in 2014.

Venezuela has since 1992 witnessed three military coups.

Maduro, who issued a televised appeal for order, said 30 people had been detained by late Thursday and that more arrests were possible.

“We are looking for all of them — we’ve identified them all,” he said of opposition activists who had scattered after skirmishing with police.

“One by one, they are going to fall and face justice,” Maduro declared on state television.

Street protests are among the few options left for the center-right opposition to pressure Maduro, whom they blame for the country’s descent into economic calamity.

Negotiations have failed and he has resisted international pressure, while retaining backing from the military and control over most state institutions. Maduro is resisting opposition efforts to hold a vote on removing him from power.

Venezuela’s next general election is due in December 2018. Regional elections last December were postponed indefinitely, and no date has been set for local polls due this year.

The collapse in energy prices has sapped the country’s revenues, prompting shortages of food, medicine and basic goods along with a surge in violent crime.

The opposition blames Maduro for the economic crisis. He says it is due to a capitalist conspiracy.

Although he has retained the crucial support of the army so far, that could be changing, political analyst Luis Salamanca said.

“At this point, Maduro can’t say he’s sure of anyone’s support,” he said, “including the armed forces.”