A North Korean passenger ferry has docked in Russia's far-eastern port of Vladivostok for the first time. The vessel will sail once a week to the port city and will also carry cargo.<br/><br/>The ferry service comes amid heightened tension between North Korea and the US over Pyongyang's missile tests and efforts to develop a nuclear arsenal. Chinese tourists are expected to use the service to visit North Korea and Russia.<br/><br/>Japan's Foreign Minister Fumio Kishida has voiced concern to Russia about the new ferry service. North Korea is under wide-ranging UN sanctions.