US and Iranian forces clashed in the Gulf, and the UAE came under renewed attack, endangering a month-old ceasefire and shaking hopes for a diplomatic solution to the crisis.

The flare-up in fighting came as Washington awaited a response from Tehran to its proposal to end the conflict, which began with joint US-Israeli airstrikes across Iran on February 28.

President Donald Trump said on Thursday three US Navy destroyers were attacked as they moved through the strait, a conduit for around a fifth of the world’s oil and liquefied natural gas flows that Iran has all but closed since the conflict started.

“Three World Class American Destroyers just transited, very successfully, out of the Strait of Hormuz, under fire. There was no damage done to the three Destroyers, but great damage done to the Iranian ⁠attackers,” Trump wrote on Truth Social.

Trump later told reporters the ceasefire was still in effect and sought to play down the exchange.

“They trifled with us today. We blew them away,” Trump said in Washington.

Iran’s top joint military command accused the US of violating the ceasefire by targeting an Iranian oil tanker and another ship, and of carrying out air attacks on civilian areas on Qeshm Island in the Strait of Hormuz and nearby coastal areas. The military said it responded by attacking US military vessels east of the strait and south of the port of Chabahar.