A Singapore-registered oil tanker was boarded by "unidentified persons" about 300 nautical miles (555 km) off Ivory Coast in the Gulf of Guinea, the city-state's port authority said. The Gulf of Guinea has become a hotspot for global piracy in recent years, although incidents have dwindled since 2021 as national authorities stepped up security efforts, helped by foreign naval ships, the United Nations says. The tanker Success 9 had 20 crew of various nationalities aboard, one of whom was Singaporean when it "was boarded by unidentified persons" on Monday, the Maritime and Port Authority of Singapore (MPA) said. In a…