Yemen's Iran-backed Houthi rebels announced a missile attack on Israel on Monday and declared a ban on Israeli shipping in the Red Sea, raising the spectre of a return to major disruption on the key route.
The Houthis harassed cargo ships in the vital seaway during the Israel-Hamas war, forcing many companies into a lengthy detour around the tip of southern Africa.
Their threat comes as the Strait of Hormuz, the gateway to the Gulf sea and its energy exporters, remains blockaded
by Iran as a result of the Middle East war with the US and Israel.
"We declare a complete and total ban on Israeli maritime navigation in the Red Sea," said a statement from the Houthis' armed forces. "We consider all enemy movements to be legitimate military targets for our armed forces from the moment this statement is issued."
The Houthis, who joined the Middle East war in support of Iran in March, had not announced a missile attack on Israel since a fragile ceasefire began on April 8.