Authorities confiscated more than $200 million in U.S. currency from methamphetamine producers in one of this city's ritziest neighborhoods, they said Friday, calling it the largest drug cash seizure in history.

The seizure reflected the vast scope of an illegal drug trade linking Asia, Mexico and the United States, officials said. Two of the seven people arrested Thursday at a faux Mediterranean villa in the Lomas de Chapultepec neighborhood were Chinese nationals.

The group was part of a larger drug-trafficking organization that imports "precursor chemicals" from companies in India and China for processing into methamphetamine in Mexican "super labs," authorities said. The methamphetamine is eventually sold in the United States.

The raid resulted from an investigation that began in December, when authorities seized 19 tons of pseudoephedrine, a cold medicine that is a key ingredient in the production of methamphetamine, at a Mexican port on the Pacific Coast.

A legally registered Mexican company, listed by a trade association as the country's third-largest importer of pseudoephedrine, was implicated, officials said.

Mexican drug-trafficking organizations have become increasingly important in the U.S. methamphetamine trade, because the U.S. has imposed tougher controls on the sale of the chemicals used to produce the highly addictive drug.

President Felipe Calderon hailed the seizure as a major development in his government's war on drug traffickers, who have ravaged several Mexican cities and towns.

"We are working in a decisive manner to save our country and to keep Mexico safe and clean," Calderon told an audience in Tijuana. "I don't even want to imagine how many young people this gang poisoned with its drugs. But I can assure you, they will do it no longer."

Mexican officials said the cash seized was mostly in U.S. $100 bills and weighed at least 4,500 pounds.

"Kudos for the Mexicans," said Donald C. Semesky, financial operations chief for the U.S. Drug Enforcement Administration. "They're very serious in this effort, and we commend them."

U.S. officials said that, if confirmed, the cash seizure would be several times larger than any other made from drug traffickers. A spokesman for the Mexican attorney general's office said that experts were still analyzing the $205.6 million in cash to check for counterfeits but that the bills appeared to be legitimate.

Officials with the attorney general's organized crime unit used a moving truck, guarded by a 25 patrol-car caravan, to take the money to its headquarters.

Authorities said the traffickers were led by a naturalized Mexican citizen of Chinese descent who appeared to have left the country.

Several machines for manufacturing pills were found at the site, but the group did not produce drugs there. The mansion appeared to serve as a financial operations center and cash storage facility.

Exclusive neighborhood

The neighborhood is home to some of the capital's wealthiest residents and many members of the diplomatic corps. The back of the property is contiguous with a racquetball court at the Ukrainian ambassador's residence. The Israeli Embassy is a few blocks away.

Most neighbors and the many maids and security guards who work in the area declined to comment on the raid. The few who did said they had no knowledge of illicit activity.

"The problem is that all of these houses are veritable fortresses," said one of the neighborhood's security guards, who asked not to be named. "You never know what goes on inside. The doors open automatically. The owners all have chauffeurs. People go in and out, and you never see anything."

A driver-bodyguard arrested at the house had told neighbors he was a retired lieutenant colonel in the Mexican army. Neighbors said he walked a German shepherd along the tree-lined streets.