The Department of Homeland Security has warned of a “heightened threat environment” in the US after American strikes in Iran. The National Terrorism Advisory System bulleti n issued Sunday doesn’t mention any specific threats, but it suggests that networks should step up cybersecurity, CBS News reports. The advisory is in effect for 90 days.

“Iran also has a long-standing commitment to target US Government officials it views as responsible for the death of an Iranian military commander killed in January 2020,” the bulletin states. “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 advisory says US law enforcement “has disrupted multiple potentially lethal Iranian-backed plots in the United States since 2020.” In a briefing over the weekend, Air Force Gen. Dan Caine, chairman of the Joint Chiefs of Staff, said the US was on “high alert” for retaliation from Iran, ” USA Today reports. “Our forces … are fully postured to respond to any Iranian retaliation or proxy attacks, which would be an incredibly poor choice,” he said. “We will defend ourselves. The safety of our service members and civilians remains our highest priority.” (Iran launched missiles at an American military base in Qatar on Monday.)