A 46-year-old man is facing drunk driving charges after his car crashed into a US Secret Service vehicle attached to President Joe Biden's motorcade, police said Monday.

The accident occurred Sunday evening about 40 meters from Biden as he left his presidential campaign headquarters in Wilmington, Delaware.

Police said that it was an "accidental collision" and the driver, a Wilmington man who was not identified, has been charged with driving a vehicle under the influence of alcohol and inattentive driving.

Security personnel rushed the president into a waiting vehicle following the accident and he was whisked away to his local residence.

Pool reporters had gathered on the sidewalk outside the campaign offices - where the president and First Lady Jill Biden had dinner with staff - and had just finished shouting questions to Biden when they heard the crash and saw him with a surprised expression on his face.

Agents sprang into action, cornering the silver car with Delaware license plates and drawing weapons on the driver, who held up his hands.

Reporters were then quickly rounded up by staff to join the motorcade as it departed the rain-drenched scene.