Russian researchers have kicked off a maritime expedition in search of gas and oil on North Korea’s shelf in the Sea of Japan (East Sea), official documents show, following Moscow’s move to spend millions of dollars on mineral exploration off the DPRK’s coast.

St. Petersburg geology and oceanology researchers began a monthlong voyage aboard the Pavel Gordienko research vessel to conduct a “gas-hydro-geochemical survey” of the seabed in the DPRK’s exclusive economic zone in May to June, according to official procurement documents.

The researchers seek to identify “aromatic hydrocarbons” in seabed sediments, among other goals, according to documents filed by