Over the weekend, Donald Trump ordered strikes on three major Iranian nuclear sites—Fordow, Natanz, and Isfahan—after reportedly learning of an Iranian sleeper-cell terror threat in the U.S. These are spies who live undetected until activated by foreign governments. A U.S. memo warned, “The threat of sleeper cells… has never been higher.”

In response, Russian President Vladimir Putin backed Iran, calling Trump’s actions “unprovoked aggression.” Speaking with Iranian officials in Moscow, Putin added, “We are making efforts to assist the Iranian people.” Iran’s Foreign Minister said the U.S. attack would be met with legitimate self-defense and thanked Russia for standing “on the right side of history.”

Security expert Will Geddes noted that Russia may have already been supplying Iran with weapons, adding, “Putin is sabre-rattling,” but his support is a serious warning.

Trump had hinted earlier at escalating action, saying of Iran’s leader: “We know exactly where… he is hiding… We are not going to take him out… at least not for now.” His ambiguous responses to reporters—“I may do it, I may not”—sparked fears of World War III.

The U.S. remains on high alert, with law enforcement bracing for potential retaliation or cyberattacks.