"In the morning, in the Nakhodka Bay near Mys Astafyeva, a gas and air mixture blasted. No blaze was observed. According to the preliminary data, two people were killed while the whereabouts of another person is unknown", the statement read.
The investigators have launched a criminal case over the incident.
A spokesperson of the Nakhodka port authority said earlier on Saturday that the blast took place on board the Zaliv Amerika oil tanker.
In 2016, another accident happened in the Russian port when the oil spill took place over an area of 1,500 square meters.