The United States has imposed sanctions on Venezuelan officials, escalating a diplomatic crisis that had already resulted in expulsions of diplomats.
The sanctions and Venezuelan President Hugo Chavez's threat to stop crude oil sales to the United States plunged ties between the superpower and one of its top energy suppliers to the lowest point in years.
Mr Chavez warned on Thursday that world crude prices would immediately double to above $US200 a barrel if he cuts oil to the US.
The clash was part of a long-brewing conflict between the US and Latin America's bloc of left-wing leaders antagonistic to US dominance in the region.
Tensions were already high after Mr Chavez allowed two Russian long-range bombers to land in Venezuela and took Moscow's side in disputes over Georgia and US plans for a missile shield in eastern Europe.
The latest crisis began when Bolivia expelled its US ambassador, accusing him of fuelling protests against leftist President Evo Morales, a close ally of Mr Chavez.
In an expletive-laden tirade against "Yankees," Mr Chavez on Thursday ejected the US ambassador to Venezuela.
Honduras weighed in on Friday, blocking a US envoy from immediately taking up his post as ambassador.
Washington has responded by throwing out envoys from Bolivia and Venezuela and freezing the assets of three aides to Mr Chavez.