Rights groups said that Reza Valizadeh, an Iranian-American journalist, was recently arrested in Iran, although the State Department did not confirm that he was the person detained.

Reza Valizadeh had worked for Radio Farda, an outlet under Radio Free Europe/Radio Liberty that's overseen by the U.S. Agency for Global Media.

"Iran routinely imprisons U.S. citizens and other countries' citizens unjustly for political purposes," the State Department said.

The US has deployed additional warships and B52 bombers as threats from Iran continue to mount against Israel.