A Mexican judge in the northern state of Chihuahua was shot dead in his office by unknown assailants, authorities said.

The victim, identified as Jose Isabel Arrieta Mendoza, was in his office Wednesday in the town of Valle de Allende when two armed men burst in and fired at him at point-blank range, Carlos Gonzalez, spokesman for the Chihuahua state Attorney General's Office, told Efe.

Arrieta Mendoza had been working for the past decade as a judge in that small northern municipality.

Authorities launched an operation to track down the assailants but no arrests have yet been announced.

Valle de Allende is a town of roughly 4,000 inhabitants in the southern part of Chihuahua, one of the Mexican states hardest hit in recent years by drug-related violence. EFE