The Strait of Hormuz remains open to all shipping except vessels linked to "Iran's enemies", Iran's representative to the U.N. maritime agency said on Sunday, after U.S. President Donald Trump threatened to target Iranian power plants if the waterway was not "fully open" within 48 hours.

The threat of Iranian attacks during the U.S.-Israeli war on Iran has kept most ships from getting through the narrow strait, the conduit for around a fifth of global oil and liquefied natural gas supplies, threatening a global energy shock.

Ali Mousavi said Tehran was ready to cooperate with the International Maritime Organization to improve maritime safety and protect seafarers in the Gulf, adding that ships not linked to "Iran's enemies" could pass the strait by coordinating security and safety arrangements with Tehran.

"Diplomacy remains Iran's priority. However, a complete cessation of aggression as well as mutual trust and confidence are more important," Mousavi said, adding that Israeli and U.S. attacks against Iran were at the "root of the current situation in the Strait of Hormuz".