Authorities in a small town in western Mexico canceled Thursday night's "El Grito" festivities ushering in Independence Day after 40 gunmen arrived at the main square threatening to attack civilians.
Michoacan state police beefed up security in the town of Querendaro because of the threat, said the state police chief, Armando Soto la Marina.
Mayor Filiberto Romero suspended the traditional event in which he was to cry "Viva Mexico!" from the balcony of the town hall, drawing the same shout in unison from hundreds of people gathered below.
But men carrying rifles and grenades arrived and demanded they clear out or be attacked. People fled in panic. Some took refuge inside the government building waiting for the gunmen to leave. There were no reports of injuries.
No information on who the gunmen were was available late Thursday, but the presence of high-caliber weapons indicated the incident might be drug cartel related.
A grenade attack on the same holiday in 2008 killed eight people and wounded dozens in the main square of the Michoacan state capital, Morelia.
Most Independence Day festivities have gone on as usual this year, but local authorities have canceled patriotic events in the past in worry about possible attacks by drug gangs. Last year, the mayor of the border city of Ciudad Juarez, considered the epicenter of Mexico's drug war, canceled the traditional event.
Ciudad Juarez 2010
President Felipe Calderon 2010
President Felipe Calderon 2011
Suspenden grito en Queréndaro Michoacán por amenazas a la población e inseguridad
Detienen a grupo armado en Michoacán