Venezuelan President Hugo Chavez has accused his Colombian counterpart Alvaro Uribe of plotting "a military provocation" against his country on the orders of the US.
"I accuse the government of Colombia of designing a conspiracy, a war provocation against Venezuela, following orders from the US, to force us to give a reply that could spark a war," Chavez said at Miraflores Palace, Spain's EFE news agency reported on Saturday.
"A military aggression is being prepared," Chavez said without offering any evidence to support the claim.
He went on to warn Colombia not to attempt any attack or other "provocation", saying Venezuela would cut off all oil exports if Colombia initiated military action.
"In that scenario, write it down, the price of oil would reach $300 (per barrel), because there wouldn't be any oil for anybody," Chavez warned.
The firebrand Chavez , a leftwing populist leader and vehement critic of the US, has repeatedly clashed with the Colombian president.
Last year, Uribe asked Chavez to mediate an exchange of hostages held by leftist Revolutionary Armed Forces of Colombia (FARC) for imprisoned rebels but abruptly cancelled the Brazilian leader's authorisation to carry out the mission.
Since then the relations between the two have soured badly.
Chavez said on Friday that it was impossible for the two neighbouring countries to have "normal" relations and noted that ties would "continue to deteriorate".