Law enforcement officers fanned out Thursday across Pittsburgh to dismantle what the FBI described as a violent cocaine-trafficking ring operating in the city.

Investigators arrested 16 Pittsburgh residents on federal charges a 17th person on state charges, authorities said.

“These are the most violent individuals who were in the city,” Richard Evanchec, special agent in charge of Pittsburgh’s FBI office, said during an afternoon news conference at the bureau’s South Side headquarters. He did not elaborate.

A grand jury indicted the defendants, who were arrested in 10 locations throughout Pittsburgh, Evanchec said.

Eight guns — including two described as “AR-style” — were recovered, along with about four kilograms of cocaine, Evanchec said.

The raids also collected MDMA, fentanyl and heroin, he said.

Pittsburgh police Chief Jason Lando said Operation Steel Reaper started when police officers in the city’s Zone 2 precinct, based in the Hill District, identified people selling drugs and guns in the area.

Officials soon uncovered a larger operation, which was targeted through a joint investigation involving the FBI, Pittsburgh police and the Allegheny County Sheriff’s Office.

“This was definitely looked at as an organization that is upstream from rival street gangs in Pennsylvania,” Evanchec said, describing their reach in distributing guns and drugs as spreading beyond the Pittsburgh region.

Steel Reaper targeted Pittsburgh-area violent drug and gun dealers, according to Bradford Arick, a Pittsburgh FBI spokesman. It was wrapped into Operation Summer Heat 2.0, a similar national initiative led by the FBI.

Pittsburgh and FBI SWAT teams were involved in four of Friday’s arrests, according to Evanchec.

The man arrested on state charges was identified as Dray Blackman, 49, of the West End neighborhood.

A Pittsburgh police SWAT team executed a federal search warrant at his house in the 600 block of South Main Street at 6 a.m., according to a criminal complaint.

Investigators said they found three guns, including an AK-47 style rifle and one that was stolen. Police said prior convictions rendered Blackman ineligible to own a gun.

They said they also found ammunition and drugs. There was heroin hidden in an electric cooking pot, and hundreds of new and unused stamp bags, police said.

While detectives were searching the residence, sheriff’s deputies took Blackman into custody during a traffic stop.

Blackman is charged with receiving stolen property and several gun and drug offenses.

Among the people arrested Thursday, Evanchec said, one had previously done time in federal custody and was on supervised release. Some were manufacturing crack cocaine, he added, and others had switches to convert semi-automatic Glock pistols to fully automatic.

Officials provided few details about the cocaine trafficking in federal court filings or during the news conference announcing the arrests.

At the news conference, Allegheny County Sheriff Kevin Kraus said he was pleased with how the operation turned out.

“I’m very glad to say everyone’s safe, they’re going to go home to their families tonight, and we’ll press on,” Kraus said.

The U.S. Attorney’s Office in Pittsburgh described DeConta Harrison, 48, of being the lead defendant, and attributed possession of at least 280 grams of crack cocaine to him.

Only a handful of defendants on the federal court docket had attorneys listed. The only one who could be reached immediately was Douglas Sullivan, who represents Jozef Bozeman, 47.

“There isn’t much that I can comment on at this point in time,” Sullivan said.

The other defendants named by federal prosecutors are:

• Charles Brannon, 54

• Rashaan Campbell, 45

• Bobby Chatman, 65

• Harold Jones Sr., 65

• William Jones, 45

• Alonzo Kidd, 50,

• Greg Nash, 65

• Jeff O’Keefe, 35

• Keith Payne, 50

• Brandon Rodgers, 41

• John Malcolm Smith, 44

• Tyisha Somerville, 32

• Kyrie Weston, 39

• Deshawn Williams, 44