(Reuters) - The United States is "deeply disappointed" the Netherlands released a former Venezuelan military intelligence chief detained over U.S. drug trafficking allegations, and is "disturbed" at reports indicating Caracas used threats to obtain his freedom, the State Department said on Monday.

Instead of being extradited to the United States, retired Venezuelan General Hugo Carvajal flew home on Sunday from the Netherlands' Caribbean island of Aruba after the Dutch government ruled he had diplomatic immunity. He had been arrested on Aruba on Wednesday.

Jubilant Venezuelan officials with the ruling Socialist Party celebrated his release as a "victory" over their ideological foes in the United States.

In an emailed statement, a State Department representative said, "We made a legitimate request for Carvajal's arrest in conformity with our treaty which governs extraditions between the United States, the Netherlands, and Aruba." The representative said Washington viewed Carvajal's claims of immunity as "beyond international norms."

Opposition politicians in Venezuela and the U.S. government say Carvajal, who ran military intelligence from 2004 to 2008, bears responsibility for years of state connivance in the illegal drug trade.

Washington put Carvajal on a blacklist in 2008, accusing him of protecting cocaine shipments from seizure by Venezuela anti-narcotics authorities and providing weapons and shelter to Colombia's FARC rebels.

Carvajal denies those charges.

'VICTORY' OVER U.S.

Venezuelan officials hailed Carvajal's release at a Socialist Party congress, calling it a "victory" over U.S. ideological foes. Carvajal was considered one of the most powerful figures during the rule of the late socialist President Hugo Chavez, a U.S. antagonist.

The case had threatened a new flare-up in long-tense relations between Caracas and Washington, as well as potentially stirring up accusations of officially sanctioned drug trading by Venezuela.

The State Department said Washington would continue efforts to bring Carvajal to justice, blaming Caracas for his release.

"We are disturbed by credible reports that have come to us indicating the Venezuelan government threatened the governments of Aruba, the Netherlands, and others to obtain this result," the State Department said. "This is not the way law enforcement matters should be handled."

The statement did not elaborate on the source of the reports or provide further details, and the State Department did not respond to a request for further information.

Carvajal himself accused authorities in Aruba of corruption during a brief appearance on stage next to Venezuelan President Nicolas Maduro at the Socialist Party Congress on Sunday night after his return.

"The judge and the prosecutor who proceed with my case are corrupt. I suspect they received money for what they did to me," he said. Carvajal gave no evidence to back up that accusation.

(Additional reporting by Andrew Cawthorne in Caracas; Editing by Jonathan Oatis)