A US Navy destroyer intercepted two oil tankers trying to leave Iran on Tuesday, a day after US President donald trump According to a US official quoted by Reuters, the blockade was announced with the aim of putting pressure on Tehran.The official told Reuters on condition of anonymity that the ships had left Chabahar Port The warship in the Gulf of Oman was contacted by radio, who instructed them to turn back. It is not known whether additional warnings were issued.The incident marks the initial phase of Washington’s blockade enforcement, aimed at forcing Iran to end what US officials describe as effectively closing the Strait of Hormuz, a vital energy chokepoint through which about a fifth of the global oil supply flows.The move comes after the failure of talks aimed at ending hostilities in the ongoing Iran-US-Israel conflict, which began on February 28, is now in its second month, and is currently under a two-week ceasefire. Trump has linked the reopening of the Strait of Hormuz to a temporary ceasefire agreement set to expire next week. A statement from US Central Command said the six merchant ships “followed instructions to re-enter an Iranian port on the Gulf of Oman”, adding that no ships had passed through there since the blockade began on Monday.However, maritime tracking data indicate that at least three ships departing from Iranian ports managed to transit the Strait of Hormuz despite a US-declared naval blockade, although some ships later turned back, according to Kpler data cited by AFP.The ships identified include the Liberia-flagged bulk carrier Christiana, the Comoros-flagged tanker Elpis and the bulk carrier Argo Maris, which reportedly passed through the chokepoint after carrying out cargo operations at Iranian ports. It is also believed that the activities were part of a wider group of at least seven Iran-linked vessels that transited the strait after the blockade was imposed on Monday.According to the military, more than 10,000 US personnel, more than a dozen warships and several aircraft are involved in the operation. Washington says it will continue to ensure freedom of navigation for ships traveling to or from Iran.However, experts have urged caution over its effectiveness. “We don’t know yet how effective it is. We’re still in the second day,” said Noam Redan of the Washington Institute for Near East Policy, noting that some ships linked to Iran have disabled the tracking system.Analysts say that if this blockade continues, tensions may increase and there may be retaliatory action from Tehran. It could also put pressure on the fragile ceasefire and further destabilize regional security.Iranian threats over shipping have already driven up global oil prices by nearly 50%. Nearly 5,000 people have been killed in the hostilities, while thousands of US strikes have weakened Iran’s military infrastructure.However, analysts warn that Tehran still remains a challenge to Washington, citing its more radical leadership and hidden stockpiles of highly enriched uranium. Redan warned that there was still a possibility of retaliation if pressure increased, saying, “We are in a testing phase.