By Nick Miles BBC correspondent in Caracas

Several people have been injured in street clashes in Venezuela between government and opposition supporters.

There were injuries in two cities on Monday

It is the latest unrest to stem from the month-long strike that has drastically reduced the country's petrol supplies and oil exports.

Venezuelan opposition leaders called the strike demanding that President Hugo Chavez calls fresh elections.

They accuse President Chavez of authoritarian rule and of ruining the economy.

Tear gas

Police fired tear gas to break up fights between the two groups in the western town of Maracaibo.

Tear gas was fired to try to break up the protests

Opponents of President Chavez broke through police lines and tried to tear down a tent set up by the president's supporters outside the offices of state oil monopoly.

Police fired tear gas to end the confrontation.

Meanwhile in Caracas there were violent scenes in the centre of the city as government supporters threw stones at an opposition group.

Several people were injured during subsequent fist fights.

Tax boycott call

The violence came as the opposition leader Carlos Ortega called on people to stop paying income tax to put more pressure on Hugo Chavez to call early elections.

There is still no sign that that is likely.

Petrol shortages are critical in many areas but Energy Minister Rafael Ramirez said on Monday that oil production would be back to a third of normal levels by next week.

Mr Ramirez said that the strike was failing, something the opposition strongly denies.