Caracas-Venezuela erupted Monday in a fifth day of violent protests against President Nicolas Maduro as the US voiced “grave concern” over moves to stifle one of his main opponents.

In the latest clashes, riot police in Caracas fired tear gas at stone-throwing demonstrators – whose leaders vowed not to let up the pressure on Maduro.

“This is a battle of resistance. We will see who gets tired first: us of fighting, or them of repressing,” said the deputy speaker of the opposition-majority congress, Freddy Guevara.

The streets of Caracas and several other Venezuelan cities have seen running battles in recent days as protesters have rallied demanding elections.

Police fired water cannons, tear gas and rubber bullets at demonstrators, who hurled rocks and Molotov cocktails, according to AFP.

Maduro is fighting efforts to force him from power over an economic crisis marked by severe shortages and the world’s highest inflation.

Pressure rose on him last week after two Supreme Court rulings that stripped the legislature’s power. The court later reversed the rulings amid an outcry.

However, the crisis deepened on Friday when authorities banned senior opposition figure Henrique Capriles from holding public office for 15 years, blocking him from running against Maduro in next year’s election.

The opposition’s demands include that authorities set a date for gubernatorial elections that have been postponed indefinitely.

Speaking at a meeting with allied leftist leaders in Cuba, Maduro said Sunday he was “eager” for the elections to go ahead so he could “hand a defeat to those people… so that they will stop the rioting and violence.”