Maduro said the hemispheric organization was persecuting his country. Although she doesn't expect change overnight, she said protesting is the only option the opposition has after what she says are scores of abuses committed by the government.
The protests are expected to be the biggest in three years, putting extra pressure on President Nicolas Maduro to negotiate with the opposition and find a way of easing the country's economic crisis.
Recent moves by Maduro to tighten his grip on power and ban Capriles from politics have escalated the country's political and economic crisis and sparked global cries of concern. The Supreme Court has blocked all reforms from opposition lawmakers.
The crisis escalated on March 30, when the Supreme Court tried to take over the powers of the National Assembly, the only lever of government Maduro and his allies do not control.
New administrations in Argentina, Brazil, and Peru notably started speaking up more about Venezuela in the previous year, in particular calling for the government to restore democratic order and hold regional elections. On Monday 11 Latin American countries, including Mercosur and Mexico, called on Venezuela's government to respect the constitutional right to peaceful protest. The opposition blamed both deaths to "colectivos", which have opened fire on protestors in every protest conducted on these past weeks.
One looming question for investors like China and Russian Federation is whether, if and when Maduro is no longer in office, Venezuela's next administration will similarly honor the terms of their respective deals, or if the new leaders would be more inclined to default.
Inflation in the country is expected to top 700% this year, according to the International Monetary Fund, despite Venezuela sitting on the world's largest proven oil reserves.
Numerous impoverished residents of the vast slums that ring Caracas and other major cities are angry about a collapsing economy and food shortages.
However, the economic crisis is hitting Venezuela's public health system the hardest.
That's making it almost impossible for the country to pay its debts and import food, medicine and other essentials for its citizens.
He also has been accused of using authoritarian methods to stop dissent.
Ricardo Rios, a mathematics professor at Central University in Caracas, said that Wednesday's march, organized by a coalition of opposition parties, was larger than the last major demonstration in September.
MARGARET WARNER: Maduro came to power four years ago, upon the death of his charismatic predecessor, Hugo Chavez.
"From the first reveille, from the first rooster crow, the Bolivarian National Armed Forces will be in the streets. saying, "Long live the Bolivarian Revolution", he said in a televised address.
4. What are the latest developments?
Today without fear millions of Venezuelans mobilized to defend the constitution, opposition governor and two-time presidential candidate Henrique Capriles said in an emailed statement.
Capriles, 44, has been the most prominent leader of Venezuela's opposition over the past decade, twice coming close to winning the presidency.
A woman of 23 was shot dead in western Venezuela on Wednesday, the second person killed during a day of anti-government protests, prosecutors and a non-governmental group said. There's also concern that Wednesday's dueling marches could lead to clashes after the No. 2 socialist leader Diosdado Cabello said 60,000 die hard government supporters would circulate on motorcycles to prevent the opposition from reaching its planned destination.
They blame their government, led by President Nicolas Maduro.