Venezuela's President, Hugo Chavez, has vowed to regain control of the country's oil industry, saying striking workers will be sacked and prosecuted for the damage they have caused.

During his weekly television and radio address, Mr Chavez said the head of the state-owned oil company Petroleos de Venezuela (PDVSA) had already started dismissing workers involved in the national stoppage.

Motorists have to wait hours to fill up

He said that vital oil exports, which have been lost an estimated $1bn of revenue during the three-week strike, were now starting again.

But union leaders have accused the president of lying, saying that there was no sign of production restarting.

"The strike continues because of the president's intransigence," said union boss Carlos Ortega.

Fuel and some basic food supplies are now scarce in many parts of the country, and the stoppage has also pushed up the price of oil on the international market.

The striking workers - who accuse President Chavez of authoritarianism and economic mismanagement - have vowed to continue their protest until Mr Chavez resigns or calls early elections.

Five tankerse

"We have begun to recover PDVSA," Mr Chavez said. "Those who didn't show up for work... they are fired."

"Not only that, we will open criminal investigations to determine the damage that has been done to the country and the Venezuelan people," he said.

The president predicted that oil output, which has been cut by 90% during the strike, would pick up from Monday.

He said five tankers have sailed in recent days, carrying 2.2 million barrels of crude oil.

But analysts said this was equivalent to just one day's normal output.

"The president is lying, lying, lying... The oil sector is still paralysed," said Horacio Medina, a PDVSA strike leader.

'Off-side'

Sunday's address was the first time Mr Chavez has mentioned sacking oil workers since a speech he made during a previous oil stoppage in April.

On that occasion he blew a football whistle and personally fired several dissident managers with the words "You are off-side".

This isn't about a small group. This is about 36,000 people who work in an oil industry Juan Fernandez, striking oil executive

That humiliating act only escalated the oil workers' strike and triggered a failed military coup against Mr Chavez.

But the Venezuelan leader's latest threat is unlikely to escalate the current strike, says the BBC's Adam Easton in Caracas.

Oil workers have already ignored a Supreme Court ruling to return to work while judges decide on the legality of the stoppage.

Ship seized

On Saturday, in its continuing efforts to combat the strike, the Venezuelan Government seized the Pilin Leon oil tanker, anchored in Lake Maracaibo, and moved it to shore to unload its cargo of petrol.

The Pilin Leon remained anchored for three weeks in Lake Maracaibo

The ship had become an emblem for the opposition, after its captain joined the strike and refused to dock.

But Mr Chavez' opponents vowed the strike was far from broken.

Juan Fernandez, one of four dissident oil executives already fired by Mr Chavez, said: "This isn't about a small group. This is about 36,000 people who work in an oil industry."