A Tamaulipas state official says a Televisa station in the border city of Matamoros suffered a grenade attack that injured two guards, one seriously.

State spokesman Rafael Luque says the two men were at the parking lot entrance late Friday when they were hit by shards of an exploding grenade.

Luque said Friday that accomplices blocked roads after the explosion so attackers could escape. They detonated another device but it did no damage.

The attack came after a week of violence in the city across from Brownsville, Texas. Enrique Juarez Torres, editor of El Manana in Matamoros, was kidnapped and released on Wednesday, a warning he said from the Gulf Cartel for reporting on gunfights that killed nine people. Fifteen people reportedly have died since last weekend in cartel violence.