FBI agents assisted by other federal, state and local law enforcement agencies fanned out across the Bay Area on Wednesday morning in a series of raids targeting organized gangs, gambling, loan sharking and money laundering.

Authorities raided more than a dozen locations throughout the Bay Area, including the Oaks Card Club in Emeryville, Artichoke Joe’s in San Bruno and several homes in Oakland, Alameda, San Francisco and San Jose. Authorities had arrest warrants for more than a dozen people. Some arrests were made but none at the Oaks Card Club.

The FBI, in conjunction with the U.S. attorney’s office, the Drug Enforcement Administration, the IRS and the state Justice Department’s Bureau of Gambling Control, executed arrest and search warrants with the help of local law enforcement agencies, including SWAT officers.

Authorities were looking for people, documents and other evidence related to illegal activities. The Emeryville and San Bruno clubs were closed for the day as agents and police conducted meticulous searches. They could remain closed for some time, officials said.

Law enforcement sources said one of the main illegal activities suspected at the clubs was loan-sharking by employees who may have ties to Chinese and Vietnamese gangs.

Authorities said players who ran out of money were approached by loan sharks who provided money so they could continue gambling — but the loans had high interest rates and some gamblers could not repay, resulting in threats against them. Authorities could not say whether anyone was ever harmed.

The FBI and other agencies had been working on the investigation for about two years. The FBI would only confirm raids were conducted, and a spokesman with the U.S. attorney’s office said he could not comment. The FBI said more information could be released Thursday.

The owner of the Oaks Card Club could not be reached for comment Wednesday. Alan Titus, an attorney for Artichoke Joe’s owners, did not immediately respond to a phone message seeking comment.

One customer present at the Oaks Card Club during the raid was Don Ramos, 35, of South San Francisco, who said he came with a friend who wanted to gamble.

Ramos, who said it was his first time at the club, estimated there were about 200 people present when dozens of FBI agents and police officers, some carrying assault rifles, came in just after 6 a.m.

“They were saying they had search warrants to search the place, but they did not say why,” Ramos said.

He said all employees and customers were searched by authorities. Ramos said he did not see anyone arrested. Authorities allowed patrons to finish their hands before proceeding with the raid.

“It’s a shocking experience. I won’t forget March 2,” he said, adding that he does not plan to return to the club.

Patrons of Artichoke Joe’s were turned away from the closed card room Wednesday. Customers and several employees said they had no idea the raid was coming and didn’t notice anything amiss before it happened. Two men who said they worked as security guards at the casino sat near one of the entrances but said they had not heard anything from the owners.

Bay Area News Group staff writer Joshua Melvin contributed to this report.