Trump says Iran shot down Apache helicopter, US must react

US President Donald Trump on Tuesday vowed to respond after Iran shot down a US military helicopter that was patrolling the Strait of Hormuz.“I have just been informed by our Great Military that last night the Iranians shot down one of our highly sophisticated Apache Helicopters while patrolling over the Strait of Hormuz,” Trump wrote in a social media post.“Nevertheless, the United States must, ‌of necessity, respond to this attack,” he said, adding that the two US pilots involved in the incident were safe and uninjured.The remarks – and a potential US response – threaten to unsettle the fragile ceasefire reached by Washington and Tehran on April 8, clouding efforts to end the war.On Monday, Israel and Iran said they would halt attacks on each other after an appeal by Trump to end their first direct exchanges of fire since April, but Tehran warned it would resume hostilities if Israel continued to attack its ally Hezbollah in Lebanon.