(Reuters) - Former Mexican Defense Minister Salvador Cienfuegos pleaded not guilty to drug charges on Thursday in a case that has put U.S.-Mexican cooperation in the fight against powerful cartels to the test.Cienfuegos, a top player in Mexico’s war on drug gangs until two years ago, was arrested at Los Angeles International Airport last month in a U.S. Drug Enforcement Administration (DEA) operation. He was transferred this week to Brooklyn, New York, where he is detained and faces trial. Cienfuegos, 72, served as defense minister for six years under former President Enrique Pena Nieto. The arrest shocked the Mexican military establishment and has put strains on security cooperation with the United States, which has become increasingly close over the past 30 years. Building the case off intercepted Blackberry messages, prosecutors say Cienfuegos used his power in office to protect a faction of the Beltran-Leyva cartel, directing operations against rival gangs and even finding maritime transport to ship drugs. Judge Steven Gold accepted the plea, made via a video link at a Brooklyn federal court. Cienfuegos is being held at the Metropolitan Detention Center, a troubled and crowded jail that also holds Ghislaine Maxwell. The next court date is set for Nov. 18 before U.S. District Judge Carol Bagley Amon, said a spokesman for Acting U.S. Attorney Seth DuCharme in Brooklyn. The proceeding is currently scheduled to be in-person. Before the hearing, Edward Sapone, a lawyer for Cienfuegos, said his client was presumed innocent of the charges in the four-count indictment. “My legal team and I will ensure that Gen. Cienfuegos’ constitutional rights are protected as we zealously defend him,” Sapone said in a statement. Mexican President Andres Manuel Lopez Obrador has criticized the lack of information shared prior to the arrest of Cienfugos and warned of a review of cooperation agreements. He has also questioned the role of the DEA and other U.S. agencies in Mexico, saying they worked closely for years with officials later accused of collaborating with criminals.