Double Grenade Attack Kills 7 Marking Mexican Independence

MORELIA, Mexico, Sept. 16 -- Assailants threw two grenades into a huge crowd of independence day revelers in the central western state of Michoacan on Monday night, killing seven people and injuring more than 100 in a brazen attack that escalates the war between Mexico's army and drug gangs.

The blasts shattered a family-friendly gathering of thousands in the cobblestone streets of this Spanish colonial city where President Felipe Calderón grew up. On Tuesday, he pledged an immediate military response.

Since taking office in 2006, Calderón has sent more than 25,000 soldiers to confront the cartels that move marijuana and cocaine into the United States, and the gangs have responded with daytime shootouts, assassinations and beheadings. Michoacan has seen more than its share of this violence.

On Monday night, Michoacan Gov. Leonel Godoy had just finished shouting "Viva Mexico!" from a balcony when the grenades exploded simultaneously, blocks apart.

At first, revelers appeared to think the explosions were part of the fireworks display. Then thick, black smoke rose, the cathedral's bells fell silent and people started screaming.

Godoy, who was unhurt, said witnesses saw a heavyset man in black throw a grenade, then beg forgiveness. But he gave no more details, and there were no arrests or assertions of responsibility. "Without a doubt, we believe this was done by organized crime," Godoy said.