There are no credible threats in Southern California, but security consultants and travelers have raised concern.
The drone strike that killed Gen. Qassem Soleimani, the head of Iran's elite Quds Force, is considered a major escalation between Washington and Iran, with Iran promising a response.
MORE: LAPD on alert in wake of US airstrike that killed Iranian general
"We will probably see a significantly heightened threat in places around the world where Iranian-backed militias and groups have a lot of influence," said ABC7 security consultant Hal Kempfer.
Kempfer says countries around the Middle East are now danger zones for Americans.
"If you don't have a reason to travel there, I would think really hard about traveling there right now," Kempfer said.
He recommends using heightened caution if traveling to Europe. In the U.S., extra security is expected.
"I'm going ahead with my travel, but I'm aware there may be bad sentiment against our country for something that I don't think most people agree with," said one visitor at LAX.
The Transportation Security Administration sent a bulletin Friday warning of the threat against surface transportation, such as trains, buses, boats and pipelines.
The acting Department of Homeland Security Secretary Chad Wolf said on Twitter, "At this time there is no specific, credible threat against the homeland. DHS operational components are implementing measures to enhance homeland security within their authorities and mission sets when necessary and prudent."
At this time there is no specific, credible threat against the homeland. DHS operational components are implementing measures to enhance homeland security within their authorities and mission sets when necessary and prudent.— Acting Secretary Chad Wolf (@DHS_Wolf) January 4, 2020
Kempfer said he expects to see more random checks of vehicles going into LAX and more law enforcement presence.