Yemen’s Houthis said Monday they had struck a Saudi oil tanker with a ballistic missile in the Red Sea, escalating their campaign against Saudi-linked shipping weeks after declaring a naval blockade on the kingdom.

What happened: The British maritime security agency, United Kingdom Maritime Trade Operations, said in the early hours of Monday that a tanker was struck by an unknown projectile about 63 nautical miles west of Yanbu, Saudi Arabia, causing a fire on the vessel’s main deck. All crew members were safe, and no environmental impact was reported, the maritime agency said. It advised vessels transiting the area to exercise caution and report any suspicious activity.

Soon after, Houthi military spokesperson Yahya Saree claimed responsibility for the attack in an X post. Saree wrote that the Houthis targeted “the Saudi enemy’s oil tanker” with a ballistic missile. “The strike was precise and direct, resulting in a fire breaking out on the tanker and the flight of several other ships that were present in the targeted area,” Saree wrote.

The Houthis also claimed to have carried out two separate operations against Saudi military forces inside Yemen.