More strain on the international shipping network emerged after Ukraine struck an Iranian cargo ship in the Caspian Sea on July 25. With the Strait of Hormuz effectively closed, and the Houthis threatening international shipping in the Red Sea, shippers must add the Black Sea and the Caspian Sea to areas that are unsafe. Ukraine said the ship was carrying military equipment between Iran and Russia. Iranian officials said it was a commercial vessel, and it accused Ukraine of killing a sailor in the attack. Iranian officials threatened retaliation in a series of statements and comments to the news media.