BERLIN — Six former employees of German gun maker Heckler & Koch are on trial for breaching arms control laws in the sale of firearms to Mexico.

At the trial's opening Tuesday, prosecutors accused the defendants of delivering almost 4,500 assault rifles, ammunition and accessories to areas of unrest in Mexico from 2006 to 2009.

Chief prosecutor Karlheinz Erkert told the Stuttgart court that the defendants knew the G-36 rifles, worth 4.1 million euros ($4.9 million), shouldn't have been exported, but that they hoped for "not inconsiderable sources of income."

Lawyers for the defendants rejected the allegations, saying the firearms were delivered to Mexican authorities who then undertook the further sale within the country.

Human rights groups say firearms delivered to Mexico often end up in the hands of drug cartels.