MEXICO CITY, Aug 10 (Reuters) - Mexican President Andres Manuel Lopez Obrador vowed on Tuesday to protect a prominent journalist after a powerful drug cartel threatened to kill her, in the latest instance of serious violence facing reporters in the country. Lopez Obrador said a protection scheme had been set up for Azucena Uresti, best known as a television anchor at news network Milenio, and who received the threat in a video message delivered in the name of the Jalisco New Generation Cartel. Surrounded by masked gunmen, a mask-wearing man accused Uresti of showing bias in coverage in favor of so-called self-defense groups battling with the gang in the state of Michoacan. Lopez Obrador, who frequently criticizes media he views as hostile to his administration, expressed "solidarity" with Uresti during his regular morning news conference. "I completely condemn these threats," he said, adding the gang"s behavior would not be tolerated. Uresti has rejected the gang"s accusations and on Twitter thanked Lopez Obrador on behalf of "all our colleagues who have been harassed, threatened and murdered in this country." Mexico is one of the world"s most dangerous countries for media professionals, according to groups dedicated to their protection. Late last year, a senior government official said nearly 140 journalists had been murdered since 2010.