Guajardo, 37, was killed during crossfire between military forces and drug traffickers in the border city of Matamoros, news reports said. Gulf cartel leader Antonio Ezequiel Cárdenas Guillén was among those killed in the confrontation.
A crime reporter with the local daily Expreso Matamoros, Guajardo left home around 11 a.m. to cover the confrontation in the Fraccionamiento Victoria neighborhood, news reports said. His pickup was reportedly shot at least 20 times as he was heading for the Secretariat of Homeland Security to gather more information. National news outlets said army officers had fired at the journalist's unmarked truck because they mistook him for one of the gunmen involved in the shooting.
The military had waged a major operation targeting Cárdenas Guillén. The army deployed 150 soldiers, three helicopters, and 17 vehicles, according to a government statement. Three soldiers and four other gang members were killed, the government said.