An alleged leader of a powerful drug gang was caught near the border with California, Mexican officials announced Monday, calling it a blow to a syndicate they say is smuggling nearly half the illegal drugs (search) crossing the U.S.-Mexico frontier.

Gilberto Higuera Guerrero was arrested before dawn Sunday at a house in the border city of Mexicali (search), Attorney General Rafael Macedo de la Concha said at a news conference.

Macedo described Higuera as "a legend" in drug trafficking, saying his gang -- the Arellano Felix organization, or the AFO -- was responsible for moving nearly half of all drugs across the U.S.-Mexican border.

In Washington, Drug Enforcement Administration Deputy Administrator Michele Leonhart said the arrest "solidifies the determination of the U.S. and Mexican governments to finish the job of dismantling the AFO."

"As we make a significant impact, they attempt to adapt and overcome. But instead ... they are being overwhelmed with relentless pressure from law enforcement," Leonhart said in a statement.

The DEA said the arrest was part of Operation United Eagles, a U.S.-Mexico fugitive-apprehension effort started in July 2003.

The U.S. State Department last year offered a $2 million reward for Higuera's capture. That was less than the $5 million it offered for his alleged bosses at the time -- brothers Javier and Eduardo Arellano Felix of Tijuana (search).

Macedo said Higuera split with the AFO late last year and is now the "principal operator" for drug boss Ismael "El Mayo" Zambada, whose Mazatlan-based gang is said to be increasing its control of drug trafficking along Mexico's western border with the United States. The split triggered a series of bloody confrontations between the two gangs.

While the United States has asked for Higuera's extradition, Macedo said he would first be tried in Mexico, where he faces nearly a dozen charges of drug trafficking, arms violations and organized crime.

Macedo said intelligence gathered by both Mexican and U.S. officials led to Higuera's arrest, but he did not elaborate.

U.S. officials have praised efforts by President Vicente Fox's administration to cripple Mexico's organized crime rings, although the country still is plagued with drug-related corruption among police and prison officials.

The Arellano Felix gang, one of the country's most violent groups, has been hit especially hard. Police in Mazatlan shot and killed Ramon Arellano Felix in February 2000, and his brother, Benjamin, was captured at his home in Puebla a few weeks later.

Higuera's brother, Ismael, a top lieutenant in the Arellano Felix gang, also was arrested in 2000.

In 2003, the Gulf Cartel's leader, Osiel Cardenas, was captured during a shootout in Matamoros, across from Brownsville, Texas.

Those arrests led to a series of detentions of second-tier drug traffickers and to turf battles all along the border that have left dozens dead. But Mexican authorities have failed to make any key arrests of members of the Ciudad Juarez-based cartel led by Vicente Carrillo Fuentes.

Earlier this month, U.S. drug czar John Walters said Mexico's efforts have caused sporadic disruption in drug supplies but no "systematic disruption or shortage."