SANTIAGO : Chile said Monday it is suing Bolivia at the International Court of Justice over a river both countries claim rights to, the latest water-related row between the South American neighbors.

Chile wants the ICJ to declare the Silala river, which originates in Bolivia and flows into Chile, an "international river" and affirm its right to its waters, Chilean Foreign Minister Heraldo Munoz told a news conference.

The battle over the small river is part of a larger dispute between landlocked Bolivia, which wants access to the Pacific Ocean, and Chile, which has nearly 4,700 kilometers (more than 2,900 miles) of coastline.

Bolivia lost its access to the sea to Chile in the War of the Pacific in the 19th century, and has stepped up efforts to get it back under President Evo Morales.

Morales has sought to use the Silala as a bargaining chip, threatening to reduce the flow of its water into Chile's parched Atacama desert and impose fees for its use.

In March, he announced plans to sue Chile over the river, insisting it only crossed the border because it had been diverted from its natural course.

Munoz said Chile had brought a lawsuit at the Hague-based court "as a necessary measure to defend our interests."