Authorities in the US state of Connecticut are investigating a possible threat against President Obama, according to local media reports.
A statement from the US Secret Service, which oversees the President's personal security, said: "Information has been received by law enforcement regarding a potentially suspicious person and vehicle. We are working with our local law enforcement partners to determine the validity of the information provided."
A local newspaper said state police were looking for a man who had allegedly made a threat against Obama.
He was believed to have been driving a car with Connecticut licence plates.
Obama was making a number of fundraising appearances in the north-east of the country on Friday.
More top news
Vauxhall showed a "reckless disregard for safety" by not stopping motorists driving Zafira B vehicles despite knowing they were a fire risk.
Police say they have rescued a woman kept captive in a pit in a shed by a neighbour with mental health issues.
North Korea is running the risk of a "major, major conflict" with the United States, Donald Trump has warned.