President Barack Obama sought to reassure Americans they are safe as millions of people traveled on Wednesday for the Thanksgiving holiday, with security heightened at airports, New York City's parade festivities and other venues after the Paris attacks.

"Right now, we know of no specific and credible intelligence indicating a plot on the homeland," Obama told reporters at the White House, flanked by his FBI director and other top security officials.

"We are taking every possible step to keep our homeland safe," he said.