CARACAS - Hundreds of thousands of Venezuelans Sunday took to the streets of Caracas in marches for and against President Nicolas Maduro's government, as the nation's massive divide became ever more visible.The protests - which began on February 4 - are seen as the biggest test yet to socialist leader Maduro since he succeeded late leftist icon Hugo Chavez last year, with the country's economic problems at the heart of often bloody scenes that have left 10 people dead and scores injured.Saturday's competing mass rallies in the capital laid bare a chasm between those who support Maduro and those who oppose him, in an oil-rich country that despite having the world's largest proven reserves is grappling with basic goods shortages, rampant inflation and violent crime.Just 24 hours after Maduro made a rare offer to US President Barack Obama of talks to end more than a decade of enmity, there appeared no prospect of rapprochement after Secretary of State John Kerry hit out at the Venezuelan government's handling of the protests.Heeding the call of opposition leader Henrique Capriles, who narrowly lost to Maduro in the election to succeed Chavez last year, at least 50,000 anti-government protesters streamed into several avenues in the Caracas neighborhood of Sucre. With some sporting Guy Fawkes masks or faces painted in the colors of the Venezuelan flag, they demanded the disarming of groups accused of intimidating and even attacking demonstrators."The state should stop these paramilitary groups," said the head of the main opposition coalition, Ramon Guillermo Aveledo. "It is unacceptable that there are armed groups that are out of control."Others accused Maduro and late leader Chavez for allowing the economy to tailspin and for failing to tackle street crime and corruption. "I can't stand the situation. It's not fair that we're in one of the richest countries in the world and still can't get food," 24-year-old student Joel Moreno told AFP. Meanwhile, tens of thousands of pro-government supporters, mostly women who clutched flowers and dressed in red and white, gathered in the center of the capital. Some of Maduro's backers, draped in the national flag, denounced the student protests. "Venezuela is a country of peace and they can't come here and try to change what it is," said Josefina Lisset, 54. "They should let this president rule, he was elected democratically."On Saturday, Maduro who denies holding links to armed groups, unveiled a new peace initiative - a week after a national public safety strategy he announced was overtaken by the protests."I am calling on the Venezuelan people to join me Wednesday in a national peace conference with all the country's political sectors ... so we Venezuelans can try to neutralize violent groups," he said.While supporters from the rival camps spilled on to the streets in different parts of the capital, security was heavy amid fears further clashes could erupt if they collided.The head of the Organization of American States, the regional bloc for the Americas, meanwhile, floated the idea of international mediation.In an op-ed piece in the Chilean paper La Tercera, Jose Miguel Insulza said that if neither government nor demonstrators in Venezuela "trusts anybody any more, no institution or person to be fair and balanced ... maybe they should resort to external actors from somewhere in the Americas" to mediate "before it is too late."As the rallies got under way on Saturday, medics announced that a 23-year-old woman shot in the face three days ago in the northern city of Valencia had died of her wounds, raising the official death toll linked to the unrest from nine to 10.The protests - which kicked off in the western city of San Cristobal led by students angry over the soaring crime rate - have increasingly been accompanied by violence and attempts to intimidate protesters.In the western state of Tachira, it was alleged that groups on motorbikes fired on people protesting by banging on pots at their windows. In Caracas, AFP journalists have in recent days also seen men on pick-up trucks escorted by motorbikes intimidating protesters.Early Saturday, Maduro said US Secretary of State Kerry's remarks that the Venezuelan government had used "unacceptable" force on protesters had effectively given violent groups a "green light" to carry out attacks.Maduro insists the protests are part of a "coup d'etat in development" instigated by Washington and conservative ex-Colombian president Alvaro Uribe, who is considered close to the United States.