BOSTON (AP) -- Thirty people have been charged in what authorities called a "dismantling" of two violent street gangs who allegedly sold crack cocaine, high-grade marijuana and oxycodone and terrorized two Boston neighborhoods.

U.S. Attorney Carmen Ortiz said state, local and federal law authorities worked together for the last 18 months to bring down the Hendry Street gang and the Woodward Avenue gang. She said 27 people were arrested Thursday, while two others were already in custody. Another man remains a fugitive and is being sought by police.

Boston police Commissioner Ed Davis said the investigation, dubbed "Operation Concord," involved drug buys by undercover officers, surveillance and a wiretap. He said the gangs had terrorized residents of the Bowdoin-Geneva section of Dorchester and the Uphams Corner section of Roxbury. The two gangs allegedly worked together to run the drug trade in the area.

"This will make a difference," Davis said.

Suffolk District Attorney Dan Conley said the arrests dealt a "major blow" to gun violence and drug trafficking in the city.

Ortiz said more than 300 federal and local law enforcement officers carried out most of the arrests early Thursday.

Authorities said 25 of those arrested are from the Boston area, one is from California and one from Maine.

"This community has been in desperate need of reprieve from the violence," Ortiz said.