NEW YORK — A 14-year-old Dutch girl who threatened a terrorist attack in a tweet to American Airlines was arrested in Rotterdam on Monday — but that didn’t stop a copycat from tweeting a similar threat to another airline.

A Twitter user named “Sarah” wrote on Twitter over the weekend that she was a member of Al Qaeda and that she would “do something really big.”

The threat was apparently meant as a joke, but American Airlines wasn’t laughing.

The airline tweeted: “Sarah, we take these threats very seriously. Your IP address and details will be forwarded to security and the FBI.”

American also issued a statement, saying “At American, the safety of our passengers and crew is our number one priority. We take security matters very seriously and work with authorities on a case by case basis.”

“Sarah” quickly backtracked, saying she was a 14-year-old white girl who made the whole thing up.

“I’m so sorry I’m scared now,” she responded to American Airlines on Twitter. “I was joking and it was my friend not me, take her IP address not mine.”

The girl then spent hours on Sunday trying to explain the tweet and beg for forgiveness. “I’m just a fangirl pls I don’t have evil thoughts and plus I’m a white girl,” she tweeted. She also pleaded: “I was kidding pls don’t I’m just a girl pls.”