TORONTO -- Nine people from southern Ontario with alleged ties to organized crime in the United States have been arrested in a major weapons and drug bust, the .

Authorities seized six kilograms of fentanyl and carfentanil, one kilogram of heroin, more than 20 kilograms of cocaine, more than 250,000 tablets of controlled substances, including methamphetamine, about three million cigarettes and several gaming machines, the force said.

RCMP Supt. Chris Leather said the four-year investigation -- dubbed Project Otremens -- involved the RCMP, Ontario Provincial Police, the Canada Border Services Agency, the FBI, and the municipal police forces of Toronto and Peel and York regions.

The nine people were arrested in raids conducted in the Toronto area, Leather said, and five others are being sought on Canada-wide warrants.

The RCMP said dealing with the trafficking of fentanyl and carfentanil is a top priority.

Fentanyl, an opioid that is 100 times more potent than heroin, has been blamed for the growing overdose crisis across the country and the U.S.

"Even more powerful substitutes are beginning to appear," Leather said. "Shipments of carefentanil and W18, which are both 100 times stronger than fentanyl, have recently been seized by police in Canada."

Leather said the accused are linked to crime families operating in New York, and several people were arrested there by the FBI for related offences.

The FBI has been conducting a parallel but separate investigation, the RCMP said, focusing on members of the Bonanno and Gambino families.

The RCMP said the investigation demonstrated the ability of those in organized crime to corrupt people in positions of public trust.

Wojciech Grzesiowki of Innisfil, Ont., who is one of the men police say is at large and a "well-known" organized crime member, allegedly convinced a Toronto police civilian employee to make "queries" of police databases for him and his organization.

Erin Maranan, the subject of a 2016 Toronto police investigation into police corruption, now faces 20 counts of breach of trust for database queries, RCMP said in a statement.

Leather said the people arrested appeared in a Milton, Ont., court Thursday for bail hearings. They face a combined total of 75 charges, including participating in a criminal organization, conspiracy to import a controlled substance and trafficking firearms.