Multiple US media say the Federal Bureau of Investigation has fatally shot a man who allegedly made online threats to kill President Joe Biden.

ABC News and other outlets say FBI agents shot and killed the man on Wednesday while serving an arrest warrant at his home in the western state of Utah.

The circumstances leading to the shooting remain unclear.

Biden was scheduled to visit the state on Wednesday evening to attend an event.

The man reportedly had posted threats on social media several days earlier, including one in which he said he had heard Biden was coming to Utah and needed to prepare his sniper rifle.

Media reports say FBI agents began investigating the man several months ago after he allegedly made online threats against politicians and public figures.

They include Vice President Kamala Harris and a prosecutor pursuing charges against former President Donald Trump related to alleged hush money paid to an adult movie star.