Federal authorities boarded two cruise ships in Boston and arrested 11 people on suspicion of receiving and distributing child sexual exploitation and abuse material.

The arrests occurred during an operation conducted between Friday and Sunday, U.S. Customs and Border Protection said. The cruise ships in question were Holland America Line’s Volendam and the Norwegian Cruise Line’s Breakaway.

Nine of the arrested people are citizens of the Philippines, one is a citizen of Indonesia and another is a citizen of Nicaragua.

None of their identities were released, and authorities did not say how many arrests occurred aboard each ship.

CBP and Homeland Security Investigations made the arrests after the subjects’ living quarters and electronic devices were searched.

All 11 people were processed for removal under the Immigration and Nationality Act for crimes involving moral turpitude, CBP said.

The arrests were part of “Operation Tidal Wave,” an initiative the CBP and HSI are undertaking in coordination with the Internet Crimes Against Children Task Force and the National Center for Missing and Exploited Children. The operation targets crew members on cruise ships, but CBP did not say if the 11 people arrested in Boston worked on the ships.

“Protecting children from exploitation is among our highest priorities, and this operation demonstrates the critical role CBP officers play in identifying and stopping individuals who pose a threat to public safety,” Julio Caravia, acting director of field operations for CBP’s Boston Field Office, said in a statement.

“Through strong coordination with HSI, NCMEC, the U.S. Attorney’s Office, and our law enforcement partners, we will continue to use every available authority to disrupt the possession and distribution of child sexual abuse material and prevent those involved from entering or remaining in the United States.”