The government of Peru is expected to file suit in the International Court of Justice in The Hague by Thursday in a dispute over the maritime border between Chile and Peru.
Peru has longed claimed the area near the Chilean port of Arica, and contends that the limits at sea between the two countries have never been defined.
Chilean President Michelle Bachelet Monday rejected Peru's claim to the area of the Pacific Ocean near their common border, saying treaties signed in 1952 and 1954 clearly define the area as Chilean territory.
The two countries have feuded over the area since Chile seized a portion of Peru in an 1879 war.
Former Peruvian Defense Minister Allan Wagner is to present Peru's complaint before the court in The Hague.
Some information for this report was provided by AP and Reuters.