Venezuela's state oil company said Tuesday that it has stopped selling crude oil to Exxon Mobil Corp. and has suspended commercial relations with the U.S.-based oil company.

State-run Petroleos de Venezuela SA, or PDVSA, said in a statement that it "has paralyzed sales of crude to Exxon Mobil." It said the decision was made "as an act of reciprocity" for the company's "judicial-economic harassment."

President Hugo Chavez has shaken oil markets this week with broader threats to cut off oil supplies to the United States. His threats came in response to a drive by Exxon Mobil to seize Venezuelan assets through U.S. and European courts in a dispute over the nationalization of its oil ventures in Venezuela.

The impact of the decision on Exxon Mobil was not immediately clear. Both Chavez and Oil Minister Rafael Ramirez previously said the Irving, Texas-based company is no longer welcome to do business in Venezuela.