JERUSALEM (AP) — A European naval force detained six suspected pirates on Friday after they opened fire on an oil tanker traveling through the Gulf of Aden, officials said, likely part of a growing number of piracy attacks emanating from Somalia. The attack on the Marshall Islands-flagged Chrystal Arctic comes as Yemen’s Houthi rebels have also been attacking ships traveling through the crucial waterway, the Red Sea and the Bab el-Mandeb Strait connecting them. The assaults have slowed commercial traffic through the key maritime route onward to the Suez Canal and the Mediterranean Sea. The pirates shot at the tanker from a small ship “carrying weapons and ladders,” according to the British military’s United Kingdom Maritime Trade Operations center, which oversees Mideast shipping routes. The pirates opened fire first at the Chrystal Arctic, whose armed, onboard security team returned fire at them, the UKMTO said.