Australia joins defensive military operation in Hormuz Strait

On 18 April 2026, Iran said it had closed the Strait of Hormuz again, citing the US naval blockade of its ports, after a brief reopening during which at least 8 tankers passed, according to trackers. Iran's navy told ships the strait was shut, and Iran said any ship approaching would be 'targeted'. Ships reported gunfire: the UK military said Iranian gunboats fired on a tanker, and two Indian vessels came under fire and turned back, after which India summoned Iran's ambassador.

Trump warned against 'blackmail', and US forces had turned back 21 vessels since the start of the blockade, according to CENTCOM. The UK and France were reported to be preparing to lead a 'defensive' mission in the strait, and Australia said it would join a defensive military operation there. The ceasefire was nearing its end.