The US and Iran have been exchanging waves of strikes, as a dispute over control of the Strait of Hormuz threatens to derail efforts to end their war.
BBC correspondent Barbara Plett Usher, reporting from Jerusalem, examines the latest tensions over the key international shipping channel.
Over the weekend, Iran announced that the strait was closed, while the US insisted it was not controlled by Iran and that traffic was flowing.
The escalation has cast doubt over the preliminary agreement that the US and Iran signed in June to end their four-month conflict and reopen the strait.