Federal Police in Mexico have arrested a number of drug dealers in Mexico City, including an associate of the country's most-wanted drug lord.

Police say Fernandez Valencia worked with the head of the Sinaloa cartel, trafficking drugs into the US. He was arrested on Monday after a 20-minute standoff between police and his drug gang. Officials say Fernandez Valencia has been wanted since 2009. He was allegedly in charge of sending 100 to 400 kilograms of cocaine to other Mexican states and the US. His arrest is the latest success of the Mexico's war on drug-related crimes, which was launched by President Felipe Calderon in 2006.