The Ecuadorean government signaled Monday that will appeal a decision by the District Court of The Hague that ruled in favor of the Chevron oil company in a long-standing dispute over contamination in the Ecuadorean Amazon.

A panel from the District Court of the Hague in the Netherlands recently ruled that an arbitration tribunal, convened under the authority of the U.S.-Ecuador Bilateral Investment Treaty, did have jurisdiction in the case and affirmed the legitimacy several interim awards favoring the Chevron oil company.

Ecuadorean Attorney General Diego Garcia said the court erred in agreeing with Chevron that Ecuador was bound to the terms of the bilateral investment treaty and its arbitration mechanism.

The investment treaty between Ecuador and the United States came into effect in 1997, a full five years after Chevron ended its operations in the country. By ruling the arbitration tribunal had jurisdiction, the District Court of The Hague is attempting to apply the treaty retroactively...