MEXICO CITY, Aug 20 (Reuters) - A U.S. federal court in Massachusetts has agreed to hear litigation filed by the Mexican government against various arms manufacturers in the United States, Foreign Minister Marcelo Ebrard said on Friday. "It is a first big step. Now comes the notification and the legal process. We"re advancing," Ebrard said on Twitter. Mexico is accusing weapons makers of reckless business practices that supply what it called a "torrent" of illegal arms to violent Mexican drug cartels, leading to thousands of deaths. Reporting by Raul Cortes; Writing by Drazen Jorgic