Iran's Islamic Revolutionary Guard Corps (IRGC) declared the Strait of Hormuz closed on Saturday, June 20, just days after the waterway had been reopened following a U.S.-Iran ceasefire deal. Tehran cited continued Israeli military strikes on southern Lebanon as a violation of the memorandum of understanding agreed with Washington earlier this week.
The IRGC warned ships not to approach the strategically vital strait, through which roughly 20% of global oil supplies transit. The closure represents a major escalation just as the ceasefire appeared to be holding, and threatens Switzerland talks planned for Sunday aimed at advancing nuclear negotiations between Washington and Tehran.
U.S. Central Command disputed the closure, stating that commercial shipping through the strait actually increased Saturday as American forces continued operations supporting freedom of navigation. The diplomatic standoff leaves the fate of the waterway—and global energy markets—deeply uncertain.