An ISIS-affiliated media outlet posted an image that depicts Pope Leo holding a soccer ball and covered in what appears to be blood.
The U.S. Embassy in Spain has sent out an alert to Americans who plan to attend Pope Leo's six-day tour through Spain this month.
This is not the first time ISIS has threatened a pontiff. Pope Francis faced similar ISIS threats during his papacy.
"The deliberate incorporation of Spanish football club imagery and a date reference tied to the Pope's itinerary suggests an intent to amplify the threat's reach and resonance among football-engaged audiences. For FIFA World Cup 2026, Spain's role as a co-host nation makes this convergence of IS targeting interest, football symbolism, and an active papal visit particularly significant," according to the nonpartisan Center for Internet Security, which monitors extremism online.
ABC News contributed to this report.