IRGC warns ships to use Iran-approved routes through Strait of Hormuz Iran's Islamic Revolutionary Guard Corps (IRGC) has warned commercial vessels to use only its approved routes through the Strait of Hormuz, reopening a point of tension in fragile negotiations between the United States and Iran over the strategic waterway. The warning came after Oman announced a new shipping transit route through the strait on Wednesday, saying it had coordinated the route with the International Maritime Organization (IMO) as traffic resumes following weeks of disruption. The dispute remains one of the unresolved issues after the US and Iran signed a Memorandum of Understanding (MoU) last week.