Updated

Authorities in Chicago on Thursday showed off eight tons of marijuana they found in a tractor-trailer, saying the drug seizure will help with efforts to combat gang violence in the nation's third-largest city.

"The competition between narcotics dealers for these markets is keen and it results in violence," said police Superintendent Garry McCarthy. "This is not the (violent) crime. This is the driver of the crime and when we make seizures like this, we can affect street level sales ... and it impacts on crime in the city."

Chicago has seen a dramatic increase in homicides this year — up about 50 percent so far when compared with the same period last year — and police blame much of the violence on the city's gangs.

Jack Riley, special agent in charge of the Drug Enforcement Administration's Chicago office, said the marijuana was grown in Mexico and shipped to Chicago for street gangs to sell. He said gangs would have been hungry for the marijuana, which has an estimated street value of $40 million. "That leads to violence," he said before Thursday's media briefing.

The announcement also came a day after the City Council passed an ordinance that allows police to write tickets instead of making arrests for procession of 15 grams or less of marijuana. The eight tons of marijuana is the equivalent of more than 7.2 million grams, prompting officers to ask each other jokingly just how many tickets so much marijuana was worth.

The jokes aside, McCarthy, who supported the ordinance, said such large seizures would go further in stemming violence than arresting people for small amounts of marijuana. He has said the ordinance will allow officers to stay on the street where they could fight crime rather than being involved in the time consuming arrest process for minor marijuana cases.

"Eliminating those markets, working on supply ... is going to make the city safe," he said.

One alderman who voted for the ordinance said a drug dealer resorts to violence to protect his criminal operations, "not the joint in his pocket."

"This (amount of marijuana) is what they're fighting for," said Alderman Roderick Sawyer. "They're fighting for money and power."

Authorities say the seizure of so much marijuana shows how Chicago is increasingly becoming a player in the often-violent international drug trade.

"Chicago is rapidly becoming a hub for the (Mexican drug) cartels throughout the country," said Riley, who said the drug dealers look at the city in the much the same way that trucking businesses and other kind of operations that distribute their products around the U.S.

"This is a perfect place to set up shop," he said.