Venezuelan President Hugo Chavez is threatening to cut off oil exports to the United States if Washington, in his words, "crosses the line" regarding his government.
President Chavez did not elaborate, but said Friday in Caracas that he has started taking measures in preparation.
Mr. Chavez's remarks came one day after U.S. Secretary of State Condoleezza Rice said Venezuela's government posed one of the biggest problems in the region and that its ties to Cuba were a particular danger to democracy in Latin America.
Venezuelan officials have demanded that Washington explain Rice's comments, saying a written request is being sent to the United States. Caracas has also demanded that the U.S. stop meddling in Venezuela's internal affairs.
Earlier, representatives from Venezuela's government met with visiting State Department officials in an apparent effort to ease tensions. Bilateral relations have grown increasingly strained since President Chavez took office in 1999.
Some information for this report was provided by AP and Reuters.