Yemen’s Houthi rebels will expand their missile operations to strike Israeli-linked ships in the Indian Ocean heading to the Cape of Good Hope, their leader warns.

Abdul-Malik al-Houthi said the Iran-backed group had already begun planning to attack ships that had diverted from the Red Sea and Gulf of Aden, its main area of operations since mid-November.

“Our main battle is to prevent ships linked to the Israeli enemy from passing through not only the Arabian Sea, the Red Sea and the Gulf of Aden, but also the Indian Ocean towards the Cape of Good Hope,” he said in a televised speech,...