I want to call on the glorious Venezuelan people to stay calm and to the army to set an example of civility, rejecting any incitement to violence

General Lucar Rincon

The bloodshed triggered a rebellion by the country's military.

Pedro Carmona, the head of the Venezuelan business association Fedecamaras, has said that he will head a transitional government at the request of the armed forces.

He said the government would be made up of military and civilian personnel, and he announced an immediate end to the general strike.

The strike has crippled the oil industry in Venezuela - the world's fourth largest oil exporter.

Oil prices fall

In London, oil prices fell at the start of trading following Mr Chavez's resignation.

Opec, the cartel of leading oil exporting nations, said it was "concerned" by the situation in Venezuela, fearing the country might increase its oil output in order to boost state finances.

Thursday's opposition rally was in support of striking managers at the state oil company, who said Mr Chavez had tried to take it over by filling the board with his supporters.

Eyewitnesses said snipers had opened fire on a crowd of more than 150,000. As well as 11 dead, more than 80 were injured.

Business leader Pedro Carmona is to head a transitional government

Mr Chavez appeared on the state-run television channel denouncing the protest, while independent TV channels were taken off the air by order of the government.

However, Finance Minister Francisco Uson, who is an army general, and National Guard chief Luis Camacho Kairuz resigned in protest at the killings.

They were joined by 10 other high-ranking military officers rebelling against Mr Chavez.

Mr Chavez finally quit after overnight talks with a delegation of generals at the Miraflores presidential palace.

Appeals for calm

"The president was asked to resign from his post and he accepted," armed forces chief General Lucas Rincon said.

"I want to call on the glorious Venezuelan people to stay calm and to the army to set an example of civility, rejecting any incitement to violence. Keep faith in your national armed forces," the general said.

The United States said it was watching developments closely.

Mr Chavez was driven away from the presidential palace to the Fuerte Tiuna military barracks in Caracas.

Opposition groups came under fire at the protest

General Efrain Vasquez Velasco said he was being held there while investigators decide what charges he could face for Thursday's violence.

Spanish radio reported that Mr Chavez had asked to be allowed to leave the country for Cuba.

The BBC's Adam Easton, in Caracas, says there are noisy celebrations on the streets, with crowds gathering at La Carlota airport in Caracas hoping to see Mr Chavez depart.

Guaicaipuro Lameda - a former army general and until recently president of Venezuela's state oil monopoly - said Mr Chavez's administration had been condemned because it began arming citizens' committees.

He said it was these armed groups that had fired at opposition protesters.

Mr Chavez's wife, Marisabel Rodriguez, was reported to have left Caracas on Thursday night with their children and flown to her home town of Barquisimeto.

Italian airline Alitalia said it was cancelling flights on Friday to and from Caracas for "security reasons" after the rioting in the Venezuelan capital.

Mr Chavez won a landslide election victory in 1998, six years after he led an abortive coup as a young army officer.