A U.S. Navy veteran was detained in Iran after he traveled there to visit his girlfriend who he met online, according to a new report.

Michael White, 46 — the first known American to have been detained in the Middle Eastern country since Donald Trump became president — is being held in connection to a “private complaint,” CBS News reported Friday, citing Iran’s semi-official Mehr news agency.

A “private complaint,” under Iranian law, refers to allegations made by a citizen, not the state.

Prosecutor Gholamali Sadeghi said the case is “still under investigation,” without elaborating, according to the report. He did not confirm reports that White could be facing national security charges.

His family claims he was arbitrarily detained, the outlet reported. His mother, Joanne White, told CBS early this month that her son never made his scheduled return flight from Iran after he traveled there in July.

The family reported him missing at the time, but only learned from the State Department in December that he was being held in an Iranian prison, White said.

“I’m very worried about his health,” the concerned mother told the network. “He just got over cancer and I’m worried about his condition. It’s very scary to me. He’s been over there three or four times without any issues. The last time I had contact with him was July 13th.”

The family had not been informed of any charges against White, his mom said. They have called on the Trump administration to secure his release — as he was still in treatment for cancer treatment and his mother worries that he might not survive prolonged detention.

White worked as a cook for the Navy and left the service about a year ago. His family spokesman, Jonathan White, told the outlet that Michael was not a spy and had never been one. He had most recently worked as a janitor.

At least four other known American citizens are being held in Iran, according to the report.

The news of White’s detention comes soon after well-known Iranian newscaster Marzieh Hashemi, 59, was released from U.S. custody after being detained for 10 days.