MEXICO CITY (Reuters) - The U.S. ambassador to Mexico on Saturday rejected President Andres Manuel Lopez Obrador's claims that the U.S. was "co-responsible" for violence in the western state of Sinaloa, where more than 50 people have died in an intra-cartel war this month.

Some 53 people have been killed and 51 others are missing in Mexico's western Sinaloa state since rival factions of the Sinaloa Cartel began clashing on Sept 9, local authorities said on Friday, with gruesome violence showing no signs of abating.

Mexican President Andrés Manuel López Obrador says the United States is partially responsible for a wave of violence in the state of Sinaloa that has left dozens dead in the past two weeks, with bodies repeatedly found on public streets and highways.

Mexican President Andrés Manuel López Obrador has blamed the United States in part for the surge in cartel violence terrorizing the northern state of Sinaloa which has left at least 30 people dead in the past week.

At least 30 people have been killed in the past two weeks in Mexico’s northern state of Sinaloa as two factions of the powerful Sinaloa cartel continue to clash.

Two warring factions of the Sinaloa cartel appear to be fighting for power since two of its leaders were arrested in the U.S.

Mexican leader says the U.S. bore some responsibility "for having carried out that operation" to arrest Ismael 'El Mayo' Zambada.

Rival factions of the Sinaloa drug cartel are waging a deadly war in northwestern Mexico, leaving dozens dead and missing in the wake of U.S. arrests of key cartel leaders. The violence between groups known as the “Mayos” and the “Chapos” erupted after U.