Cocaine and marijuana seizures in the southwestern United States and along Mexico's Pacific coast have escalated dramatically in the past two years, alarming U.S. law enforcement authorities who say Mexican traffickers are sending greater quantities and larger loads of drugs into the United States.

Seizures of marijuana by U.S. agencies along the southwestern U.S. border, where 70 percent of all illicit drugs enter the country, were up as much as 33 percent over last year, according to U.S. drug interdiction agencies. Between 1991 and 1998, seizures have jumped from 113 tons to 720 tons. At the same time, cocaine loads off Mexico's Pacific coast appear to have increased dramatically, and this year the U.S. Coast Guard made the largest cocaine hauls in its history in both the Pacific Ocean and the Caribbean.

The heavier flow of drugs has exacerbated ongoing problems of trust and cooperation between U.S. and Mexican authorities, and is particularly troubling to U.S. law enforcement in light of new statistics showing rising marijuana use among American teenagers.

The rising number of seizures reflects not only greater smuggling activity but also dramatic increases in drug production in Colombia and Mexico, according to U.S. officials and reports from law enforcement agencies. U.S. authorities estimated that they capture 10 to 15 percent of all drugs smuggled into the country. While many officials credited improved coordination among U.S. law enforcement agencies for the increase in seizures, they said the trend clearly indicates more drugs are arriving in the United States.

The year's mounting tally of drug seizures, along with new U.S. calculations of significantly increased cocaine production in Colombia and expanding opium poppy and marijuana production in Mexico, are sending "shock waves through the system," said a senior U.S. official involved in monitoring drug trafficking.

Mexican authorities disputed some of the U.S. conclusions, but said they would not compile Mexican seizure totals until next month and declined to discuss this year's trends until their figures are made public. Earlier this year, Mexico's top anti-drug official, Mariano Herran Salvatti, said he believed that cocaine shipments into Mexico had dropped 50 percent this year, but he did not provide detailed supporting data.

Herran said at a news conference this summer that marijuana and poppy yields were up in Mexico because eradication was becoming increasingly difficult, noting that "the illicit plantations are turning ever more away from populated areas and into federal lands in the mountains."

Mexican drug cartels appear to be reorganizing their operations to improve the transport of South American cocaine and Mexican marijuana and heroin to the United States at a time when many Mexican anti-drug units are in disarray and have made little progress in targeting the country's biggest cartel leaders, according to U.S. law enforcement agencies.

"The drug groups are flexible and innovative and are using ever more sophisticated and well-organized counter-surveillance and counterintelligence," according to a new U.S. government intelligence assessment. "They are constantly . . . identifying and exploiting law enforcement predictability, patterns, weaknesses, vulnerabilities and routines."

While politicians at the highest levels of both countries' governments continue to say that cooperation has improved, Richard A. Fiano, chief of operations for the U.S. Drug Enforcement Administration, told a congressional subcommittee in September, "Until such time that adequate anti-corruption assurances and safeguards can be implemented, DEA will exercise extreme caution in sharing sensitive information with our Mexican counterparts."

Fiano described the "investigative achievements" of Mexico's most elite anti-drug units against major cartels as "minimal." A special fugitive apprehension team created by Mexico's anti-narcotics agency to track down the leaders of the Tijuana-based Arellano-Felix cartel, one of Mexico's two largest drug mafias, "has not participated in any significant enforcement activity," Fiano said.

Mexican political leaders this year became so frustrated with failed attempts to clean up the country's corrupt law enforcement agencies that they created a new national police force for fighting drug trafficking and other crime. Top political leaders also pledged a multimillion-dollar increase in support to the military and existing civilian agencies for counter-narcotics efforts.

The surge in Mexican marijuana shipments comes in the face of new U.S. government statistics showing that marijuana use among American youth between the ages of 12 and 17 has doubled in the past six years. In the first nine months of 1999, marijuana seizures nationwide were up 29 percent, from 513 tons during the same period last year to 663 tons this year.

Although those figures include domestically produced marijuana, the seizure figures for Mexican marijuana were up by even more staggering amounts. Border-wide seizures were up about 33 percent, and in southeastern Texas--which has become the hottest transit zone on the international boundary in recent months--marijuana seizures were up nearly 70 percent over last year, according to law enforcement agencies.

In February, five tons of Mexican marijuana were seized at one southern Texas residence, and a month later another five tons were captured at a second home.

"Despite record border seizures, Mexican marijuana remains readily available," DEA officials wrote in the intelligence report. "Mexico-based trafficking organizations . . . have enhanced and strengthened their production, smuggling and distribution capabilities to ensure a continuous supply of drugs to U.S. communities."

At the same time, cocaine loads also have expanded dramatically, according to U.S. records. Cocaine loads have become so large off Mexico's Pacific coast that the U.S. Coast Guard is planning to launch unprecedented armed helicopter assaults against boat traffickers similar to a highly classified program tested in the Caribbean earlier this year against smaller, high-powered, high-speed boats carrying drugs from Colombia, according to Coast Guard officials.

While Colombian cocaine traffickers and the Mexican cartels that handle the transportation of their cocaine were first detected using the wide open Pacific sea lanes in the mid-1990s, law enforcement officials said they were stunned by the large caches discovered in recent months.

On Aug. 13, the Coast Guard nabbed a Mexican shark fishing boat stuffed with 10.5 tons of cocaine about 500 miles off Acapulco. It was the largest cocaine bust ever made off the Mexican Pacific coast and the second biggest sea seizure ever by U.S. law enforcement.

On June 15, the Coast Guard seized 7.7 tons of cocaine in another Mexican fishing vessel 500 miles offshore.

Overall, Coast Guard cocaine seizures in the Pacific and Caribbean were up 35 percent this year compared with 1998, agency officials said. While U.S. law enforcement agencies working along the southwest border have been suspicious of cooperating with their Mexican counterparts, U.S. Coast Guard authorities said cooperation with the Mexican navy in maritime seizures has never been greater.

As for opium and heroin, the cultivation of the opium poppy in Mexico has increased 30 percent since 1990. Although Mexican authorities have eradicated more acres of poppies each year, they have been unable to keep up with improved yields. In 1998, Mexican authorities reported yields 25 percent higher than in 1997, according to figures provided to the State Department by Mexico.

"The increase in poppy cultivation is particularly worrisome as it led to an increase in heroin production," the State Department wrote in this year's drug assessment of Mexico.

At the same time, Mexican seizures of opium in 1998 were less than half of those in 1997, cocaine seizures were the lowest in four years, and heroin seizures were one-third the amounts of three years ago. Marijuana seizures have continued to increase slightly every year.

CAPTION: Stemming the Flood (This chart was not available)