MEXICO CITY, Mexico (AP) — Prosecutors in northern Mexico say a drug cartel lieutenant has been detained in a series of firebombing attacks on a PepsiCo subsidiary, the Mexican potato-chip company Sabritas.

Experts say the weekend fire-bombings were the most violent and concerted attack on a private transnational company in Mexico to date in the country's five-and-a-half-year drug war.

The state-owned Petroleos Mexicanos oil company has suffered hundreds of non-violent fuel thefts from pipelines and the kidnapping of some of its employees. But Mexico's drug cartels have usually not openly attacked large private companies.

In four attacks between Friday and Sunday, several warehouses and dozens of Sabritas delivery trucks were torched.

Prosecutors in Guanajuato state said yesterday they have arrested several suspects including a lieutenant of the Knights Templar drug cartel in the attacks.

Gerardo Gutierrez, president of Mexico's Business Coordinating Council, said yesterday that it was "an isolated case" of the kind of extortion that gangs have previously practised with small and medium-sized businesses. He called on authorities to act immediately to prevent the practice from spreading.

"What we cannot

allow is for this kind of isolated case to become generalised," Gutierrez said. "The authorities have to take forceful action."

In a speech to an

anti-crime conference yesterday, President Felipe Calderon said drug cartels threaten growth and development and called them "an obstacle to prosperity because they attack companies large and small."