The United States is warning of a “heightened threat environment” after President Trump ordered strikes on three Iranian nuclear sites on Saturday evening.

The Department of Homeland Security (DHS) issued a National Terrorism Advisory System (NTAS) bulletin on Sunday, alerting the public to the potential of cyberattacks carried out by those who support Iran or are affiliated with the Iranian government.

“The ongoing Iran conflict is causing a heightened threat environment in the United States. Low-level cyber attacks against US networks by pro-Iranian hacktivists are likely, and cyber actors affiliated with the Iranian government may conduct attacks against US networks,” the bulletin read.

The bulletin also noted that the Iranian government, in recent years, has sought to target U.S. government officials it deems responsible for killing the former Iranian military officer, Qasem Soleimani.

“The likelihood of violent extremists in the Homeland independently mobilizing to violence in response to the conflict would likely increase if Iranian leadership issued a religious ruling calling for retaliatory violence against targets in the Homeland,” the bulletin read.

The bulletin warned that the ongoing conflict “could contribute to US-based individuals plotting additional attacks” on U.S. soil that are “motivated by anti-Semitic or anti-Israel sentiment.”

“It is our duty to keep the nation safe and informed, especially during times of conflict. The ongoing Israel-Iran conflict brings the possibility of increased threat to the homeland in the form of possible cyberattacks, acts of violence, and antisemitic hate crimes,” DHS Secretary Kristi Noem said in a statement to The Hill.

Trump announced Saturday evening that U.S. forces bombed three Iranian nuclear sites and said to Iran in a social media post, “NOW IS THE TIME FOR PEACE!”

The bombs targeted three nuclear sites in Natanz, Esfahan and Fordow, located inside a mountain. Six “bunker buster” bombs were reportedly dropped on Fordow, while more than two dozen Tomahawk missiles were launched at the other two sites.

The bombings put the U.S. directly in Iran’s crosshairs for retaliation and made it an active participant in the Mideast war, which Israel launched with airstrikes against Iran on June 13.