Thousands of people are once again taking to the streets of Caracas, as the capital of Venezuela braces for another day of rival protests amid escalating tensions over the country's political crisis.

Opposition leaders called for women to march on Saturday dressed in white, a traditional show of defiance, against what they brand a repressive government led by President Nicolas Maduro.

Al Jazeera's Lucia Newman, reporting from Caracas, said the march had started in the eastern part of the city and was heading towards the foreign ministry.

"There is no doubt that they will never make it [to the ministry]," Newman said.

"Riot police are out in force, already armed with water cannons and tear gas to make sure that the opposition march could not get from eastern Caracas to the western part."

In contrast, the government announced it would be organising its own women's march in the western part of the capital, a traditional pro-Socialist stronghold.

Speaking from Caracas, Phil Gunson, an analyst with the International Crisis Group, told Al Jazeera that the situation on the ground is a "battle of resistance", with neither side seeming to give in at this point.

Deadly protests

At least 37 people have been killed and hundreds wounded in more than a month of anti-government protests, as demonstrators blame Maduro for growing food shortages and the world's highest inflation rate.

The state prosecutor's office, which has kept an official count of deaths since protests began in early April, confirmed that a 20-year-old protester had died after being in a protest on Friday.

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Fatalities have included supporters of both sides, bystanders and members of the security forces. Gunshot wounds have been the most common cause of death.

Activists accuse the security forces of using excessive force, including firing tear gas canisters directly at people and allowing pro-government gangs to attack demonstrators.

The opposition, which won parliamentary elections at the end of 2015, is calling for a presidential election and for Maduro, whom they accuse of trying to create a dictatorship, to step down.

"The regime is falling," said Lilian Tintori, wife of jailed opposition leader Leopoldo Lopez, outside the prison near Caracas where she was demanding to see her husband.

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The opposition is also boycotting Maduro's constituent assembly process, aimed at re-writing the constitution, saying it is a ploy to keep him in power by setting up a body with mechanisms to ensure a government majority.

"We're not going to participate in this fraudulent process. It would validate a fraud. I confess that I'm extremely worried because we're witnessing a country that's increasingly falling into chaos. The crisis is deepening by the day and Venezuela is plunging more into anarchy," opposition leader Henrique Capriles told Al Jazeera.

Polls show the ruling Socialists would badly lose any conventional vote due to four years of economic crisis that has led to debilitating food and medicine shortages.

Despite massive oil reserves, Venezuela slipped into the worst economic crisis in its history.

Maduro blames the situation on falling oil prices and says the crisis is due to a US-backed capitalist conspiracy.

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The protests on Saturday come after some controversy surrounding the alleged arrest of 85 Venezuelan military officers for criticising Maduro's government - an announcement that was made by Capriles.

"There is discontent in the armed forces," Capriles said, adding that he had been told about the number of arrests by the military directly, who asked him to make the information public.

Venezuela's defence minister later denied that any military officers had been detained.