CARACAS (AFP) - Venezuela's opposition refused Wednesday to take part in talks that were called by the government in a bid to halt three weeks of protests that have left 14 dead.

"We will not lend ourselves to a sham dialogue that would end in a mockery of our compatriots," the opposition coalition MUD said in a letter to Vice President Jorge Arreaza.

President Nicolas Maduro had called a "national peace conference" for later in the day, but so far only the country's leading business federation and Venezuela's Roman Catholic church have confirmed they would attend.

The opposition's main leader Henrique Capriles had earlier said he would not attend, dismissing the talks as a government photo op.

MUD, an umbrella group that includes most opposition parties said the government was responsible for the current crisis.

And it accused of "excessive repression that has included the participation of armed civilians convened by the authorities." Oil-rich but deeply divided Venezuela has been swept by student-led protests since February 4, posing the greatest challenge yet to Maduro's 11-month-old government.

Maduro has sought to deepen the socialist, anti-American policies of his charismatic predecessor and mentor, the late Hugo Chavez.

But public anger over shortages of food and other basics, soaring inflation and rampant crime has served as kindling for street violence.

Maduro has responded to the street protests with force, arresting scores of demonstrators as well as a prominent opposition leader, Leopoldo Lopez.

"The government talks of dialogue, it talks of peace, but it's only an empty appeal... to go to the Miraflores palace to have a picture taken," Capriles said in a radio interview.

Caracas was calm Wednesday morning after a night of occasional clashes in the capital.

But the opposition and the government staged separate marches, in a vivid display of the polarization roiling a country with the world's largest oil reserves.

Several thousand women dressed in white marched through the city to a military barracks to demand "an end to the repression and violence by the security bodies." "We know that it's the Cubans, an invading army, who are giving the orders," said a document the women planned to deliver at the barracks.

"Don't let them." Mr Lopez's wife, Lilian Tintori, led the march with opposition deputy Maria Corina Machado.

Meanwhile, thousands of government supporters marched toward the presidential palace to rally for "peace" and against what Mr Maduro insists is an opposition "coup d'etat."