The UK has warned sailors in the Persian Gulf over apparent attempts by Iran’s military to order ships to enter Iranian waters.

In a notice published on Friday, the UK Maritime Trade Operations centre (UKMTO) said there had been “several incidents involving VHF radio challenges to vessels”, some of which included “demands to alter course”.

The UKMTO said it believed the incidents were related to a large-scale military exercise being carried out by Iran’s Islamic Republican Guard Corps (IRGC), called Great Prophet XVIII.

The two-month-long exercise comes amid ongoing tensions with Israel that have seen the two nations exchange fire in the past year.

The UKMTO added: “These exercises have warned mariners that vessels whether in or near to Iranian territorial waters may experience VHF hailing.”

On Friday morning, the UKMTO also reported a “suspicious approach” made by a military vessel towards a ship in the Persian Gulf.

The approach involved the vessel “flashing a green laser light towards the bridge” of the ship and hailing it with orders to turn towards Iranian waters.