Police in Venezuela have fired tear gas and rubber bullets to disperse anti-government protesters who were blocking several major roads into the capital, Caracas.

The clashes came as a general strike against President Hugo Chavez entered its third week and marked an escalation of tension in the political crisis.

The nation's army chief also stepped into the dispute, saying the strike paralysing the oil sector amounted to sabotage and that his troops were firmly behind the president.

Organisers of the strike began building blockades at dawn on Monday.

Rival bands

Over the next seven hours, police officers intervened on about 10 occasions to disperse protesters and clear streets blocked with rocks, containers, tree branches and burning tyres.

Police met stones and burning tyres with tear gas

Police said residents had thrown stones at them from their windows.

In southern Caracas, police fired tear gas and rubber bullets to disperse rival bands of stone-throwing demonstrators at an opposition barricade.

About 500 opposition protesters and 100 Chavez supporters had traded insults across a six-lane highway.

Protesters had also set up roadblocks on several stretches of highway in the east of the city.

The president's opponents accuse him of economic mismanagement and authoritarian rule.

Mr Chavez has described Venezuelans who support the protest as coup plotters, insisting that he will not be forced from office.

Troops have been told to follow presidential decrees

The president has told the army to follow nobody's orders but his own.

He said that troops should ignore judges and court rulings and obey only presidential decrees.

Army chief General Julio Garcia Montoya gave clear backing for Mr Chavez, saying the strike was ''an aggression against the survival of the state'' and ''an attack on the vital interests of the nation''.

The new round of opposition protests came after a weekend rally that drew about one million people.

The strike has led to petrol shortages, panic buying and shuttered shops.

Strike leader Carlos Ortega has called for immediate elections and has accused Mr Chavez of wanting ''confrontation and violence''.