The U.S.-based group SITE Intelligence Group, which monitors militant internet traffic, forwarded the Arabic-language claim to reporters on Tuesday.
It wasn’t immediately clear where the Islamic State of Iraq and Syria released the claim.
Sunday’s shootings took place in the central Jordanian town of Karak. Hours after the initial attack, four gunmen were shot and killed by Jordanian security forces during a standoff at Karak Castle, a Crusader fortress and tourist destination.
The ISIS claim said “four soldiers of the Caliphate” armed with machine-guns and hand grenades carried out the attacks.
Jordanian officials have not said who they suspect is behind the attack, but security sources said the perpetrators were Jordanian nationals.
Linda Vatcher, a 62-year-old retired teacher originally from Burgeo, N.L., was among the 10 killed.
Vatcher was visiting her son, Christopher Vatcher, who works in the Middle East. He also was shot, and was among the about 34 people who were wounded.
Michael Luedee, who was the principal at the Corner Brook, N.L., elementary school where Vatcher once taught, called her “a fantastic, empathetic and compassionate individual.”