Mexican federal police officers will be permitted to operate in the United States under new guidelines governing anti-drug cooperation between the two countries, Mexican and U.S. officials said yesterday.

The guidelines were described by U.S. officials as a sign that U.S.-Mexican cooperation had not been hindered by the recent controversy over the abduction of Humberto Alvarez Machain, a Guadalajara doctor wanted for the 1985 torture-murder of DEA agent Enrique "Kiki" Camarena.

But, in a sign of continued sensitivities, a Mexican government spokesman flatly denied a report in the Los Angeles Times that the Mexicans have agreed to permit Drug Enforcement Administration agents to carry guns in their country.

"By no means, will DEA agents operate with weapons in Mexico," said Gustavo Gonzalez-Baez, a legal attache at the Mexican Embassy in Washington. "We will not allow that, neither officially nor unofficially."

The guidelines have been negotiated by U.S. and Mexican law enforcement officials over the past few weeks in talks that were spurred in large part by the Alvarez Machain dispute. After disclosures that DEA had approved plans for the doctor to be abducted and delivered to the United States to stand trial, Mexican officials charged that U.S. drug agents had violated the country's "sovereignty" and demanded that there be "new rules" governing the operations of law enforcement officers on both sides of the border.

Resolving the matter was considered crucial to U.S. anti-drug efforts because officials believe as much as half of all the cocaine entering this country is being flown from Colombia into Mexico and then smuggled across the southern border.

A key part of the "new rules" is what the Mexicans call "reciprocity" -- permitting Mexican Federal Judicial Police officers to investigate drug cases in the United States in the same way that DEA agents operate in Mexico.

Under the guidelines, the Mexicans will be authorized to send the same number of federal police officers here as the DEA has in Mexico, U.S. officials said. DEA spokesman Con Dougherty said the agency now has "between 40 and 50" of its agents in Mexico.

Robert S. Ross Jr., an aide to Attorney General Dick Thornburgh who is overseeing the Justice Department's new international affairs office, said the precise arrangements governing the operations of Mexican police officers here had not yet been worked out. But he said "they would be working very closely" with DEA investigating drug trafficking and other criminal organizations that operate on both sides of the border.

At the same time, Mexico has agreed to broaden diplomatic immunity protection to all DEA agents in their country, not just those stationed at the U.S. Embassy in Mexico City, said Dougherty. He said that agreement "does not mention" permission for DEA agents to carry guns.