Jose Vicente Rangel said Venezuela decided to take a harder line after the United States pulled the visas of three officers previously involved in anti-drug efforts with the U.S. Drug Enforcement Administration.

"The Venezuelan government ... will proceed quickly, with responsibility, but firmly to reciprocate in the cases of U.S. citizens who travel to our country," Rangel said at a news conference.

The visas of three military officers, including two generals, who worked with the DEA were revoked after Venezuelan President Hugo Chavez accused DEA agents of spying in Venezuela and said cooperation with the U.S. agency would be suspended.

Three lower-ranking officers were put on a watch list, meaning they would be denied U.S. visas if they applied for them.

U.S. Ambassador William Brownfield denied that DEA agents were involved in espionage.

Rangel said DEA agents in Venezuela also worked with "unacceptable autonomy" while "detaining and interrogating Venezuelans" without notifying Venezuelan authorities.

The vice president said DEA agents maintained "strange ties" with drug traffickers in Venezuela, which often serves as a corridor for Colombian cocaine destined for the United States and Europe.

Ryan Methany, a spokesman for the U.S. Embassy in Caracas, declined to comment on why the military officers' visas were revoked, saying the records are confidential.

Relations between the United States and Venezuela, the world's fifth largest oil exporter, have grown increasingly strained since Chavez survived a short-lived 2002 coup.

Chavez, who has close ties to Fidel Castro, accused the Bush administration of fomenting the military rebellion, an allegation U.S. officials deny.

He claims the United States backed opposition groups that helped organize a presidential recall last year. Chavez, who won the vote by a large margin, is up for re-election next year.