Iran says it has captured two container ships seeking to exit the Gulf via the Strait ​of Hormuz.

It's Iran's first seizure of vessels since the war began in February. A third vessel was also fired upon. Montenegro's minister of maritime affairs says the Panama-flagged MSC Francesca was one of the ships captured and that the crew are safe - including four ​Montenegrin seafarers.

As the Strait remains effectively closed, vessels are being tracked by what is known as the Automatic Identification System or AIS.

• GUEST: Matt Smith, Director of Commodity Research at Kpler