The flare-up, which both nations blamed on the other, comes just one day after Tehran announced it was considering a U.S. proposal to end the war.

U.S. Central Command (Centcom) described the incident as an "unprovoked attack," reporting that Iranian forces launched "multiple missiles, drones and small boats" at three U.S. Navy guided-missile destroyers transiting the strait.

Trump, posting on Truth Social, said Iran "trifled with us today" and confirmed the U.S. destroyed multiple Iranian assets.

"Centcom does not seek escalation but remains positioned and ready to protect American forces," the command stated, noting it had "eliminated inbound threats and targeted Iranian military facilities responsible for attacking US forces, including missile and drone launch sites; command and control locations; and intelligence, surveillance and reconnaissance nodes."

Trump warned that the future of the peace deal depends on Tehran’s immediate cooperation.

"Just like we knocked them out again today, we'll knock them out a lot harder, and a lot more violently, in the future, if they don't get their Deal signed, FAST!" Trump posted.

Iran's top military command offered a conflicting account, alleging the U.S. targeted an Iranian oil tanker and carried out "aerial attacks" on coastal areas, including Bandar Khamir, Sirik, and Qeshm Island.

Tehran reported "explosions" within the city and accused the U.S. of a "violation of the ceasefire."

Iranian Foreign Minister Abbas Araghchi condemned the U.S. actions on X, stating: “Every time a diplomatic solution is on the table, the US opts for a reckless military adventure.”

He added: “Whatever the causes, the outcome is the same: Iranians never bow to pressure and diplomacy is always the victim.”

The instability spread early Friday to the United Arab Emirates.

The UAE Ministry of Defence reported its air defences were "actively engaging" a separate Iranian attack involving two ballistic missiles and three UAVs, which resulted in three "moderate injuries."

While Trump maintains the ceasefire is in place, the scale of Friday's combat—ranging from naval skirmishes to strikes on coastal nodes—highlights the extreme fragility of the current diplomatic efforts.