DUBAI, U.A.E.: Diplomatic efforts to restore global energy supplies and ensure a second round of talks between the United States and Iran suffered a setback when Iran opened fire on a third ship on April 22 in the Strait of Hormuz.

Iran's paramilitary Revolutionary Guard launched an attack in the morning after U.S. President Donald Trump extended the ceasefire with Iran just hours before it was due to end. This gave Iran more time to prepare a "unified proposal" for possible talks.

Soon after, another ship was fired at in the same strait, but it was not damaged, according to the British military's United Kingdom Maritime Trade Operations Center.

Nour News, Fars, and Mehr all reported the attack on a vessel called the Euphoria by the Guard. They said the vessel had become "stranded" on the Iranian coast, without elaborating. The Guard has seized the other two ships that were attacked, Iranian state television reported.

The agency did not say who carried out the second attack, but many suspected Iran, as its leaders seem ready to take a tougher stance in future negotiations after earlier talks with the Trump administration led to conflict.

Late on April 21, hardline supporters of Iran's government held rallies across the country. During these events, the Revolutionary Guard publicly displayed missiles and launchers for the first time since the ceasefire began, signaling defiance toward the U.S. and Israel, which had targeted Iran's missile systems in earlier airstrikes.

Although U.S. and Israeli airstrikes on Iran have stopped, and Iran is no longer launching missiles at Israel or the wider Middle East, the latest attack in the Strait and earlier U.S. actions against Iranian ships show that tensions at sea remain high. Without a diplomatic deal, such incidents could continue and disrupt global energy supplies.

Trump said the U.S. would keep blocking Iranian ports, a move Iran has called unacceptable and one reason it has not yet agreed to join talks in Islamabad.

The Revolutionary Guard warned it would strike back strongly against what it called enemy targets in the region.

These latest attacks in the Strait of Hormuz followed U.S. actions over the weekend, when it seized an Iranian container ship after firing on it and boarded an oil tanker linked to Iran in the Indian Ocean.

According to the UKMTO, the first ship was attacked at 7:55 a.m. by a Revolutionary Guard gunboat that opened fire without warning, though no one was hurt. However, Iran's Nour News said the ship had ignored warnings before the Guard fired. The semiofficial Fars news agency described the action as Iran enforcing its control over the strait.

In normal times, about 20 percent of the world's oil and natural gas passes through this key waterway, which connects the Persian Gulf to the open sea. It remained fully open until the U.S. and Israel attacked Iran on February 28, starting the war.

Since then, Iran has restricted shipping in the area, causing oil prices to rise sharply and affecting economies worldwide.