A third priest has been killed in the "hot lands" region of Mexico's southern Guerrero state.

The bishop of the diocese in Ciudad Altamirano said Friday that the Rev. Gregorio Lopez Gorostieta was found dead with a gunshot wound to the head near a highway on Christmas Day.

Lopez Gorostieta disappeared on Monday from the seminary in the city where he taught. His truck was later found abandoned near the seminary.

Many other priests have been robbed or briefly abducted in the region, which is dominated by drug cartels.

Bishop Maximino Martinez said the diocese is calling on authorities to investigate the killers and bring them to justice.