Tens of thousands are gathering across Venezuela to march in protest against President Nicolás Maduro.
At least four people were said to have died in clashes before the protests, as riot police mobilised to guard demonstrators.
National Assembly president Juan Guaidó, who organised the opposition march, urged the army to disobey the government.
The US government has signalled its support for Guaidó and called for President Maduro to go.
Early images from Wednesday’s protests showed some demonstrators facing off against National Guard security forces in the capital Caracas, and tear gas being fired.