WASHINGTON (AP) — The Supreme Court is struggling with whether to allow a lawsuit by Muslim men claiming religious bias by the FBI to go forward.

The government has said doing so could reveal national security secrets. The case involves three men from Southern California.

They filed a class action lawsuit claiming that the FBI spied on them and hundreds of others in a surveillance operation. A lower court dismissed almost all their claims after the government said allowing the case to go forward could reveal “state secrets."

But an appeals court reversed that decision in 2019. A number of justices Monday seemed to suggest the case should be sent back to a lower court.