WASHINGTON (AP) _ Senate Majority Leader Trent Lott says he's astonished that Mexican President Ernesto Zedillo has criticized a U.S. law enforcement operation that netted dozens of arrests and millions of dollars in drug profits.

Zedillo criticized the ``Operation Casablanca'' sting, partly because the United States used undercover agents on Mexican territory. Mexico has lodged a formal protest with the United States.

In a letter to Zedillo, released by Lott's office, the majority leader said the criticism contrasted with the pledges Zedillo had made in conversations with Lott about how he intended to crack down on drug kingpins.

Rejecting Zedillo's statement that the operation was ``inadmissible'' and a violation of Mexican sovereignty, Lott, R-Miss., called it ``decisive action against ruthless criminals.''

``It should be welcomed by all governments interested in combating those who profit from trafficking in illegal narcotics,'' he wrote.