Federal riot police prepare to enter to end a riot at the state prison on the outskirts of the border city of Ciudad Juarez March 4, 2009.(Xinhua/Reuters Photo) Photo Gallery>>>

    MEXICO CITY, March 4 (Xinhua) -- Gang fighting in a prison in Ciudad Juarez of the northern Chihuahua state killed 20 and injured six on Wednesday, the prison's director Oscar Hermosillo said.

    Spokesman from Chihuahua's government Victor Valencia de los Santos said that 18 prisoners died inside the prison and the other two died after they were sent to hospital.

    Valencia said the clash between rival gangs began from early morning on Wednesday and was controlled within two hours.

    The General Justice Prosecutor from the State's office (PGJE) said the clash was between the gangs known as "Los Mexicles" and "Artistas and Asesinios (AA)", who fighting for the control in the prison.

    Both gangs have had clashes for drug and weapons deals inside the prison.

    Rifles, knives and iron pins were used in the fighting. Some prisoners were thrown by their rivals from the second floor.

    Some 200 soldiers from the Mexican Army, 100 federal policemen and 150 state and municipal officers controlled the prison with assistance of military helicopters.

    Ciudad Juarez is one of the most violent cities in the country. It borders with El Paso, Texas of the U.S., and is on one of the main routes of drug trafficking to the U.S.