An American who was reportedly captured while fighting alongside terrorists in Syria "can't be very bright," a State Department official said Thursday.

"As a U.S. government, we say: Don't go do that!" State Department spokeswoman Heather Nauert told reporters at a press briefing. "You can't be very bright if you're going to go over there and do that."

That jibe stood as a placeholder for direct comment on an issue that could create tension between the Trump administration's stated goal of killing every foreign fighter who joined the Islamic State, and the constitutional due process rights of American citizens. U.S. officials across the government have declined to comment publicly on the issue.

"I don't know where this man is," Nauert said. "I can only tell you that we are aware of reports that a U.S. citizen was fighting for some sort of terror group, whether it was ISIS or not — I do not know. It serves as a good reminder that in a nation of 330-some million people, some people will be dumb enough to go Iraq and Syria to try to fight for ISIS."

Justice Department officials declined to comment on the case. The Department of Defense referred the Daily Beast, which first reported on the individual's capture, to the State Department, but Nauert said she had no more information.

"Thanks DOD!" Nauert said. "Stop referring questions to the State Department when we don't have any information about who this person was."