Suspected drug hitmen have murdered a popular Mexican politician and four of his aides.
Local police say the men were ambushed on their way to a campaign event.
Rodolfo Torre Cantu, 46, of the International Revolutionary Party was the front-running candidate for governor in the border state of Tamaulipas.
His killing indicates how far intimidation by drug cartels has reached.
Mexico’s President Felipe Calderon condemned the murders.
“It is an event not only against one candidate from a political party but also against democratic institutions,” the president said.
“It is an event that demands a unified and firm response from all of us who believe in democracy.”
Tamaulipas is one of the main trafficking corridors for drugs heading to the US market. Recently there has been a spate of fatal shootouts as two cartels battle for control.
His death comes as a blow to President Calderon who has vowed to continue his fight against drug gangs.