Defense Secretary Pete Hegseth said the war with Iran is now expected to cost Americans $37.5 billion, up from a $29-billion estimate in early May.

U.S. law enforcement and intelligence agencies have tracked evidence for years of Iranian efforts to target President Trump, with signals only increasing since the start of the war.

President Trump's grievances with several European governments over their refusal to join the U.S. war with Iran have cast a pall over the summit.

Historians say the nation's 250th anniversary has become a politicized spectacle, a celebration of an imperial presidency.