A Mexican journalist who worked in one of the areas with the most crime in the country was killed by gunmen last night, and two police officers who were in charge of his security were wounded, local authorities said.

An online news portal run by reporter Alejandro Martinez confirmed his death. The page covers local news and crime in Celaya, the most dangerous city for police in Mexico.

Celaya police said Martinez was shot by assailants traveling in another vehicle. The two bodyguards are in hospital, but their condition is not known.

The journalist received police protection after reporting that he was receiving threats. The state prosecutor's office in Guanajuato said it was investigating the murder.

Martinez was reporting a fatal highway crash just hours before he was attacked. His wounded bodyguards took him to hospital, where he died.

Guanajuato has the highest homicide rate among all of Mexico's 32 states, largely due to the years-long war between the Jalisco drug cartel and the local Santa Rosa de Lima gang. A total of 18 policemen have been killed since the beginning of the year in Celaya, a city of about half a million inhabitants. Drug gangs are suspected of most of those murders.