Wilmington, Delaware - A car crashed into a Secret Service vehicle attached to Joe Biden's motorcade on Sunday, with the security scare startling the president as he left his campaign headquarters in Delaware.

After a loud bang caused by a sedan slamming into an SUV positioned in a nearby intersection about 130 feet from Biden, security personnel rushed the president into a waiting vehicle and he was whisked away from the building in downtown Wilmington.

"Both the president and first lady are fine," a White House official told an AFP reporter who witnessed the incident.

"Today, at approximately 8:09 PM, a Secret Service vehicle securing the president's motorcade route was struck by another vehicle in Wilmington," Secret Service spokesperson Special Agent Steve Kopek said.

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"There was no protective interest associated with this event and the president's motorcade departed without incident," he added.

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 from a distance 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.

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"They're evacuating, you guys gotta go," a staffer told reporters as security personnel secured the area.

Biden arrived safely at his family home without further incident.