A new ferry line between isolated North Korea and its neighbor Russia docked for the first time at the Russian Pacific port of Vladivostok on Thursday.

The ferry's Russian operators say it is purely a commercial venture, but it coincides with what some academics say is a drive by North Korea's leader, Kim Jong Un, to build ties with Moscow in case its closest ally China turns its back.

Journalists were unable to see passengers disembarking from the ship, the North Korean-flagged Mangyongbong, because Russian officials kept them away from the quayside, citing unspecified security reasons.