An explosive rigged boat was behind an attack on a tanker off the Saudi port city of Jeddah on Monday morning, the kingdom's Energy Ministry said. "These destructive terrorist acts, directed against vital installations, go beyond targeting the Kingdom, and its vital facilities, to targeting the security and stability of energy supplies in the world and the global economy," a statement from the ministry said. The ship's owner had initially said it was hit by an "external source," which started a fire on board. The blast occurred just after midnight as the Singapore-flagged tanker BW Rhine was discharging its cargo, tanker company Hafnia said. No injuries were reported among the 22 crew members, which was later confirmed by the Ministry of Energy. The ministry statement added that there were "no injuries or loss of life, thank God, and no damage was caused to the fuel unloading facilities, or any impact on supplies." Hafnia said the ship's hull was damaged and that some oil might have leaked from the vessel, although this has yet to be confirmed. “Instrumentation currently indicates that oil levels on board are at the same level before the incident,” the company said. The vessel halted discharge operations and switched to emergency procedures onboard. The United Kingdom Marine Trade Operations, an organisation under Britain’s royal navy, urged ships in the area to exercise caution and said investigations were ongoing. It later said Jeddah port had been shut down for a “duration unknown,” without elaborating. The explosion occurred less than a month after a Greek-operated oil tanker was attacked at another Saudi oil terminal on the Red Sea. The Saudi-led coalition fighting Houthi rebels in neighbouring Yemen called it a "foiled terrorist attack" by the rebels. The Iran-backed Houthi rebels have previously used sea mines in their long war against a Saudi-led coalition. The Houthis did not, however, claim responsibility for Monday's incident. Oil prices advanced during the opening session on Monday on positive news of the vaccine rollout in the US and UK and an attack on a tanker off the coast of Saudi Arabia. Brent, the international benchmark, was up 1.08 per cent trading at $50.51 per barrel at 1.11pm UAE time, while West Texas Intermediate, the key gauge for US oil, was up 1.07 per cent at $47.07 per barrel. The Red Sea is a vital shipping lane for cargo and global energy supplies, making any mining of the area a danger not only to Saudi Arabia but to the rest of the world. The mines can be carried away by currents, which change by the season in the Red Sea.