THE HAGUE, Netherlands (AP) -- Judges at the top U.N. court sided with the West African country of Equatorial Guinea in a fight with neighboring Gabon over which treaty settled the ownership of three largely uninhabited oil-rich islands.

The decision effectively hands the islands to Equatorial Guinea.

The countries brought their dispute to The International Court of Justice in 2021, asking judges to determine what legal agreement settles the possession of the oil-rich islands.

The 15-judge panel found a 1900 treaty between Spain and France, which divided up colonial holdings, to be the ultimate authority.

A later agreement, known as the 1974 Bata Convention, which gives the islands to Gabon, was dismissed as "not a treaty having the force of law," Judge Julia Sebutinde said.

The document was contested by Equatorial Guinea and Gabon did not produce an original copy for the court.

Equatorial Guinea had control of the territory until 1972, when Gabon took over the largest island, Mbanie, in a military skirmish. When oil was discovered in coastal waters, the dispute reignited.

The economies of both countries are highly dependent on oil, but production from existing areas has been in decline in recent years.

The countries asked the court to settle the ownership question after repeatedly failing in efforts to find a diplomatic solution.