CARACAS: Riot cops fired tear gas at protesters in Venezuela Monday as thousands demonstrated against President Nicolas Maduro's efforts to reform the constitution in a deadly political crisis.
Masked protesters responded by hurling rocks and other projectiles in clashes in the capital Caracas, with other violence reported in the western states of Merida and Zulia.
Supporters of the opposition Democratic Unity Roundtable (MUD) were trying to march to the education ministry under the slogan "No to the dictatorship."
They blame Maduro for an economic crisis that has caused food shortages and say his constitutional move is a ploy to resist calls for early elections.
Education Minister Elias Jaua has been appointed by Maduro to set up an elected constituent assembly to rewrite the constitution.
Clashes at protests have left 36 people dead and hundreds injured since the unrest erupted on April 1, according to authorities.
Jaua invited the opposition to a meeting on Monday about the constitutional reforms.
"The doors are open, especially to the spokespeople of the MUD. Dialogue is the way forward," he said.
The opposition has refused to take part in the assembly.
Opposition congressional speaker Julio Borges rejected the plan as "constitutional fraud."
Government supporters staged counter-demonstrations.
Maduro says the crisis is a US-backed capitalist conspiracy.
Private polls indicate Maduro has low approval ratings, with citizens increasingly frustrated about shortages.
"I lost my husband because we could not get hold of medicine. There is no medicine and no food," said Isabel Morales, 68, demonstrating against Maduro in Caracas.
"We cannot go on like this."