The text messages popped up on cellphones across the country, purporting to be an urgent communication from the United States Army.

“We tried contacting you through your email several times and have had no response,” one message read. The recipient, it said, had been “marked eligible” for the military draft and was ordered to report to the nearest Army branch “for immediate departure to Iran.”

From New Jersey to Utah to Florida, similar fraudulent messages have circulated around the country this week, setting off concern among young people and their parents amid an escalation in conflict between the United States and Iran. But after receiving multiple calls and emails about the messages, which in at least one case threatened jail time, the United States Army issued a “fraud alert” warning that the messages were fake and said it was investigating who was behind them.