(NewsNation) — As Independence Day approaches, the Department of Homeland Security has issued a warning about potential domestic threats amid tension in the Middle East.

Cities from across the United States are monitoring for possible Fourth of July threats and have increased security out of an abundance of caution.

DHS Secretary Kristi Noem on Monday said her department is on alert but hasn’t seen any credible threats or suspicious activities in the U.S. following Saturday’s strikes in Iran.

“My responsibility is to secure the homeland and do all I can to make sure that we’re identifying threats, that may be here what we can do to get in front of them … but also to work with our local governors and law enforcement to make sure that they recognize potential threats,” Noem said.

The DHS is monitoring for possible violent extremists or cyberattacks under a “heightened threat environment.”

Police in several cities are now stationed outside places of worship and other sensitive sites. Though Noem didn’t mention a specific concern surrounding the Fourth of July, cities are still making preparations ahead of the holiday.

Mayor Steven Meiner of Miami Beach, Florida, said his jurisdiction will have a high-risk protocol in place.

“We have many measures like license-plate readers, we can utilize state and county resources, which we do. We also have a lot of undercover work,” Meiner told NewsNation.

Police departments across the U.S. couldn’t release specifics on officer staffing plans for safety reasons, but multiple precincts told NewsNation they are prepared should they come across credible threats.