A North Korean vessel instructed a South Korean cargo ship sailing in the East Sea to move farther into international waters earlier this month, Seoul has confirmed, the latest encounter between the two Koreas near their contested maritime border.

An official at the oceans ministry, speaking on condition of anonymity, told NK News that crewmembers on the DPRK vessel gestured to the ROK-flagged ship “to move to the open sea” during the incident on May 8, without transmitting messages through maritime communication channels. The official did not specify whether the North Korean ship was a civilian or military vessel.