Authorities seized several U.S. diplomatic bags at Venezuela's main airport on Thursday, prompting protest from embassy officials and a probe into the Americans' actions by prosecutors.

Attorney General Isaias Rodriguez said prosecutors would investigate U.S. officials for allegedly sidestepping official regulations and checkpoints when bringing the diplomatic bags into the South American country.

Rodriguez made the announcement after Venezuelan National Guard troops seized the bags earlier Thursday from four U.S. embassy vehicles stopped outside Caracas' Simon Bolivar International Airport. The vehicles had just picked up the bags from a U.S. military aircraft on the tarmac, he said.

CountryWatch: Venezuela

The U.S. embassy had notified Venezuela's foreign ministry that four diplomatic bags were arriving on the plane, but "many more" were found in the vehicles, he said.

"They contained supplies for the (Venezuelan) armed forces," Rodriguez told reporters. He did not elaborate or say why U.S. officials would be sending supplies to Venezuela's military. No arrests have been made.

The incident was likely to raise tensions between Washington and Venezuela's leftist government.

U.S. Embassy official Brian Penn told Globovision television that Venezuelan authorities — not U.S. officials — had acted "illegally" by confiscating the bags. He said the U.S. government would formally protest the incident.

"The embassy of the United States has protested this move by the security forces of the Venezuelan government," said Penn. "They violated diplomatic and international laws."

Penn said the bags contained personal possessions belong to embassy personnel and denied those sent by the embassy at retrieve them had violated any regulations at the airport.

Mari Pili Hernandez, Venezuela's deputy foreign minister for North America, said that officials were reviewing the contents of the bags because they hadn't been inspected by Venezuelan customs officials.

Relations between the countries have been tense in recent months due to allegations by Venezuelan President Hugo Chavez that the United States is conspiring against his government, something Washington denies. U.S. officials, meanwhile, have said they believe Chavez represents a threat to stability in Latin America.