Venezuela's president has said he will nationalise a series of oil projects in the Orinoco river belt within months.
Mr Chavez has set a deadline of 1 May for state control of Orinoco projects
Hugo Chavez was speaking as he signed a law granting him the authority to rule by decree for the next 18 months.
Mr Chavez said the government the operations, run with five international oil firms, would be state-owned by the beginning of May.
Energy Minister Rafael Ramirez said that the government would seize the operations if no agreement was reached.
"I have given instructions that on 1 May - 1 May - all the fields of the Orinoco Belt should wake up under our control," Mr Chavez told a news conference.
Under Mr Chavez's plans, Venezuela will take on majority stakes of 60% in four projects which process the crude oil in the country's eastern Orinoco Belt.
He said that he hoped the foreign firms would remain as minority partners.
The decision affects the oil firms Chevron, Exxon Mobil, Conoco Phillips, Statoil and BP.
The White House has said that it hopes that US firms will be treated "in accordance with international regulations".
The Venezuelan leader also lashed out at his arch-enemy US President George W Bush, who said on Wednesday that the concentration of political power could damage democracy in the country.
"The president of the United States should resign, if he had the least dignity ... if only the United States had a democracy like what we have here. If only the American people could call a recall referendum."