Iran on Saturday announced the closure of the Strait of Hormuz, accusing the United States and Israel of violating the memorandum of understanding (MoU) that ended the Middle East war, according to Iran's semi-official Mehr news agency. Iran's top joint military command said the closure of the strategic waterway was the "first step" in response to the alleged violations and warned that additional measures would follow if what it described as "aggression" continued. The announcement came a day before Iranian and US officials are scheduled to hold talks in Switzerland under the framework of the ceasefire agreement signed earlier this week.Iranian authorities also linked the decision to recent Israeli strikes in Lebanon, saying the attacks amounted to a breach of the ceasefire arrangements and necessitated immediate action.The Strait of Hormuz, located between Iran and Oman, is one of the world's most critical energy chokepoints, handling a significant share of global seaborne crude oil and liquefied natural gas shipments. Any disruption to traffic through the narrow passage raises concerns over global energy supplies and shipping routes.However, US Vice President JD Vance said Washington had seen no evidence that Iran had actually closed the Strait of Hormuz. Speaking to Fox News, Vance said the United States had no indications that maritime traffic through the waterway had been halted.The conflicting claims add fresh uncertainty to the fragile ceasefire reached between Washington and Tehran and threaten to complicate Sunday's negotiations in Switzerland aimed at stabilising the region after months of conflict.