Americans do not face a credible and immediate terror threat, President Barack Obama declared on Wednesday, in an attempt to reassure jittery Americans traveling home for Thanksgiving.

Obama stressed that security services are working around the clock to keep the United States safe, reported the AFP news agency.

As millions of Americans loaded into cars, planes, trains and buses to head home for Thursday’s national holiday, he urged calm.

“I want the American people to know… that we are taking every possible step to keep our homeland safe,” Obama said, trying to strike a balance between putting the public at ease and appearing complacent.

Fears in the United States have been heightened since gunmen identified as belonging to the Islamic State (ISIS) group killed 130 people in attacks across Paris on November 13.

In the wake of the Paris attacks, ISIS has threatened to attack the White House and has also threatened Times Square in New York, though officials downplayed those threats.

The State Department on Monday issued a worldwide travel alert, warning of “increased terrorist threats” and calling on Americans to “exercise vigilance”.

“It’s understandable that people worry something similar could happen here,” Obama said Wednesday, following a meeting with his top national security advisors in the Situation Room.

But, he said, “right now, we know of no specific and credible intelligence indicating a plot on the homeland, and that is based on the latest information I just received.”

Thanksgiving is a major holiday in the United States, not only for travel but also for bargain-hunting shoppers who pack malls on so-called “Black Friday” when stores offer deep discounts.

Homeland Security Secretary Jeh Johnson delivered the same calming message Wednesday at Washington’s Union Station, according to AFP.

“We are working overtime to protect the homeland. To evaluate and re-evaluate what we see,” he said.

“We also want to encourage the public at the beginning of this holiday season to be vigilant yourself and to be aware if you see something, say something. It has to be more than a slogan,” added Johnson.