MEXICO CITY — In a rare break from normally cordial relations, U.S. and Mexican officials have exchanged sharp criticisms after the Bush administration warned that U.S. citizens' lives are at risk in an escalating drug war at the border.

Mexican officials yesterday angrily condemned the State Department warning as exaggerated. But U.S. officials said it was their responsibility to alert Americans to a "deteriorating" situation in northern Mexico.

U.S. State Department spokesman Richard Boucher said yesterday that 27 U.S. citizens had been kidnapped in Mexico in recent months. Two were killed, 11 remain missing and 14 were released, he said.

In Mexico City, Interior Secretary Santiago Creel said the Bush administration "went too far" when it issued a consular report Wednesday suggesting that local authorities were incapable of controlling a spike in slayings and kidnappings after the arrests of several drug kingpins.

Creel said the warning ignored the deployment of hundreds of federal troops and agents to the region last week. He suggested the United States was not doing its job in fighting the drug war.

The tone of the exchange recalled the frequent flare-ups between a string of U.S. administrations and the prickly nationalists who ruled Mexico for 71 years under the banner of the Institutional Revolutionary Party, or PRI. Sensitive to the loss of half their country's territory to the United States in the 19th century, Mexican leaders often accused Washington of bullying and interference.

That appeared to change under Fox, whose election as the head of the National Action Party, in 2000 ousted the PRI. The new leader, who took office about the time President Bush did, played up their friendship and, until this week, picked just two quarrels: He canceled a 2002 visit to Bush's ranch in Texas to protest that state's execution of a Mexican convict on death row, and he opposed the U.S. invasion of Iraq.

Fox's office issued a statement yesterday saying that the State Department warning "did not reflect the situation in the country" and that Mexico would not accept the judgments of foreign governments.

The State Department announcement warned U.S. citizens traveling over the border that they cannot necessarily count on protection from Mexican authorities.

"Mexico's police forces suffer from lack of funds and training, and the judicial system is weak, overworked and inefficient," the announcement said. "Criminals, armed with an impressive array of weapons, know there is little chance they will be caught and punished."

The warning was quickly followed by a letter from U.S. Ambassador Tony Garza to Foreign Minister Luis Ernesto Derbez and Mexican Attorney General Rafael Macedo de la Concha.

While applauding Fox for his "strong expressions of concern," Garza wrote he was worried that "the inability of local law enforcement to come to grips with rising drug warfare, kidnappings and random street violence will have a chilling effect on the cross-border exchange, tourism and commerce."

Officials attribute the increase in violence to a vacuum of power resulting from Mexico's arrests of Gulf cartel kingpin Osiel Cardenas and Tijuana drug chief Benjamin Arellano Felix over the past three years. Other drug traffickers now are trying to conquer their border turf.