A Mexican photojournalist has died after being shot in the head in front of his house in the northern border town of Tijuana, officials say.

Margarito Martinez, 49, has worked in Tijuana for more than 10 years for several national and international news outlets, reporting on crime and gang violence in the city on the US-Mexican border.

The attorney general's office said officers who responded to the ambulance call found Martinez's body in front of his house with a head injury caused by a firearm.

One of his colleagues said Martinez was involved in a state program aimed at protecting the lives of journalists.

Tijuana is one of the cities in Mexico with the most violence due to clashes between drug gangs fighting for smuggling routes.

Martinez is the second journalist killed this year in Mexico since the death of Jose Gamboa last week in the southeastern state of Veracruz.

From 2000 to 2021, the human rights group "Article 19" registered 145 murders of journalists in Mexico, and last year seven journalists were killed.