MEXICO CITY - Mexican authorities yesterday announced the arrest of one of the country's most wanted drug trafficking suspects, for whom the United States had offered a $2 million reward.

Adan Medrano Rodriguez was detained by agents of Mexico's Federal Agency of Investigation in the northern state of Tamaulipas on Wednesday night, Justice Department officials told a news conference. He was transferred early yesterday to Mexico City, where he is being detained.

Medrano, the alleged right-hand man of presumed Gulf drug organization leader Osiel Cardenas, also was wanted by the FBI, the U.S. Drug Enforcement Administration and Interpol on drug charges, and for allegedly threatening federal agents in Texas.

Mexican authorities staking out Medrano captured him as he was trying to get into a sport utility vehicle without license plates, said Justice Department Special Prosecutor Estuardo Bermudez Molina.

Medrano, who allegedly organized operations in the northern zone of the drug gang's Gulf coast drug-trafficking corridor, was carrying a .38-caliber pistol, but did not resist arrest, Bermudez said.

Medrano gained stature in the organization after Cardenas' former alleged first lieutenant, Juan Manuel Garza, surrendered to U.S. authorities in Texas last June.

Medrano is wanted in Mexico on charges of cocaine trafficking, attempted murder, illegal arms possession and organized crime. U.S. authorities have requested his extradition to face charges of possessing and attempting to distribute marijuana and threatening federal agents.

Police say that on Nov. 9, 1999, Medrano, Cardenas and other assailants stopped a car with diplomatic plates in Texas, and threatened the lives of the three occupants, including an FBI agent and a DEA agent.

The United States offered a $2 million reward for Medrano's capture, but Mexican authorities are not eligible to receive the money, Bermudez said.

Some of the informants who helped Mexican authorities find Medrano will receive some of the money, however, he said, without elaborating.

U.S. authorities also have offered a $2 million reward for Cardenas, who remains at large. Cardenas allegedly inherited a large portion of the Gulf organization after former leader Juan Garcia Abrego was arrested in 1996. Garcia is serving 11 life terms in the United States.

Police allege that the Gulf organization is one of Mexico's top drug-smuggling operations.

Bermudez described Medrano's arrest as a "major advance" against the group: Both of the organization's powerful lieutenants have been captured.

Medrano joins a growing list of important drug-related arrests in Mexico recently. The most significant was the capture on March 9 of Benjamin Arellano Felix, allegedly the brains behind a large Tijuana-based drug organization police say he ran with his brother Ramon Arellano Felix.

Investigators say Ramon, on the FBI's 10-most-wanted list, was killed in a shootout with police on Feb. 10 in the Pacific resort city of Mazatlan.

On March 14, federal agents captured Manuel Herrera Barraza, alias "El Tarzan," allegedly the Arellano Felixes' principal smuggler of marijuana and cocaine into the western United States.