A tanker near Oman reported being struck overnight, with another saying it saw an explosion nearby as Iran warned Washington that the U.S. military's blockade of the Strait of Hormuz would result in the closure of key shipping routes.
Separately, Kuwait said its air defenses confronted hostile drone attacks by Iran.
The latest conflict comes amid U.S. media reports that U.S. President Donald Trump is preparing for a fresh round of strikes against Iran as early as this weekend, as hopes of a negotiated end to the war that began on February 28 recede and energy prices climb.
Iran's Foreign Minister Abbas Araqchi told his Saudi counterpart in a phone call on Saturday that any "aggression" by the U.S. and Israel or participation of regional countries will be met with a "decisive and proportionate response," according to Araqchi's Telegram account.
The United Kingdom Maritime Trade Operations Centre (UKMTO) said Saturday it received a report of a tanker being hit by an "unknown projectile which has caused damage to the engine room."
The tanker is not under command and the regional Coast Guard have been informed. There are no reported casualties or environmental impact.
Over the last week, the U.S. completed a "heavy wave" of strikes against Iran, hitting dozens of Islamic Revolutionary Guard Corps targets. In retaliation, Iran attacked U.S. military bases in Kuwait and Bahrain.
Egypt said Thursday that a drone hit two ships at its Mediterranean port of Damietta, triggering a fire.
The conflict, which began on February 28, continues, and energy prices are rising.
