The Secret Service detained a man who drove up to a White House checkpoint and claimed to have a bomb in his vehicle, security officials told CNN.
There was no confirmation on whether there was any device in the vehicle, but security at the White House was immediately upgraded on Saturday night.
The vehicle is being checked, the officials said.
The incident occurred at 11.05 p.m., according to the Secret Service.
President Donald Trump is not at the White House. He is at his Mar-a-Lago estate in Florida.
Several streets around the White House remained closed early Sunday in what the Secret Service described as an “on-going criminal investigation”, reports CNN.
Earlier on Saturday, another person was arrested after jumping over a bicycle rack in front of the White House.
The man, who never made it to the White House fence, was carrying a document he wanted to deliver and did not have a weapon, a law enforcement official said.
The incidents come a week after a man breached the White House grounds — and was on the grounds for more than 15 minutes.