The U.S. military issued a statement Sunday urging its personnel to maintain "vigilance" after a "kill list," allegedly made public by hackers sympathetic to the Islamic State group, went online this weekend.

The list was posted online by the “Islamic State Hacking Division” and had targeted about 100 U.S. troops. It included names and addresses of U.S. military personnel, along with a call for ISIS “brothers residing in America” to kill them. While the ISIS-linked group claimed that the data were obtained by hacking military servers and databases, U.S. officials said that most of the information was available in public domain, BBC reported.

“Vigilance and force protection considerations remain a priority for commanders and their personnel,” Lt. Col. John Caldwell, a U.S. Marine Corps spokesman, said in a statement. The marines are recommended to “check their online/social footprint, ensuring privacy settings are adjusted to limit the amount of available personal information.”

While the validity of the ISIS “kill list” is yet to be ascertained, the Pentagon said that it would investigate the matter.

The ISIS-linked group said in the online threat that the military personnel mentioned in the list had participated in U.S.-led missions against the extremist group. “Now we have made it easy for you by giving you addresses, all you need to do is take the final step, so what are you waiting for?” the group said in the post.