Demonstrators filled the center of Venezuela's capital Caracas on Thursday in the biggest show of opposition to President Nicolás Maduro in years.

Organizers, from a coalition of 19 opposition parties, claimed 2 million participated in the marches in six states around the country as well as in Caracas. In the capital they chanted "This government will fall" and sang the national anthem in one of the city's main boulevards.

Anger at Venezuela's left-wing government has escalated and spread in recent months thanks to a major economic crisis that includes near-paralysis of domestic production, chronic shortages of basic goods, the highest inflation rate in the world, and no sign of any improvement in the near or medium term.

The march was organized to pressure the country's electoral authorities to call a referendum on Maduro's future before January 10, which would mean new elections if he lost. Any later than that, and the opposition could only hope to vote out the president, who would then be replaced by his vice president.

The protesters allege that the National Electoral Council is doing the government's bidding and dragging its feet organizing the vote.

The demonstrations took place despite tight government control of key roads and rallying points. Some foreign journalists, who had travelled to Venezuela to cover the protests, were denied entrance to the country.

Allí está la fuerza del cambio!Allí está un Pueblo que tiene claro su camino:REVOCATORIO!Viva Venezuela! — Henrique Capriles R. (@hcapriles)1 de septiembre de 2016

Earlier this week President Maduro had claimed the marches were designed to hide a coup attempt. On Thursday he told a relatively small pro-government demonstration in Caracas that the plot had been foiled.

"What happened to the coup? Well it didn't take place because we defeated it," he said. "This is another victory for the people, for peace, and for the revolution."

Maduro added that his government had arrested 92 Colombian paramilitaries close to the presidential residence. He also charged that some politicians were carrying explosives, and accused opposition congressional leader Henry Ramos of being involved in the plot.

Despite the tension there were only a few reports of clashes during the marches. The last major wave of protests in 2014 led to the deaths of 43 people and the imprisonment of opposition leader Leopoldo López who was later convicted of inciting the violence.

Follow Alan Hernández on Twitter: @alanpasten