During a visit to a naval base on Bolivar Island, which sits 24km from the disputed archipelago, Santos said "These islands are, have been and will remain Colombian."

The islands, which include San Andres, Providencia and Santa Catalina, have been controlled by Colombia since the 1928 Esguerra-Barcenas Treaty. Nicaragua has long challenged Colombia's control over the islands as the treaty went into effect when the Central American nation was under U.S. military occupation. Although a judge ruled in favor of Colombia's sovereignty over San Andres in 2007, a new dispute was taken to the International Court of Justice (ICJ) at the Hague in April, primarily concerned with defining maritime boundaries around several small islands that Nicaragua feels were unclearly designated when the treaty was signed over 80 years ago.

An ICJ solution to the decades-long spat is not expected for months.

Nicaragua claims sovereignty over a 50,000 sq km area of the Caribbean, including the San Andres archipelago and adjacent islands.

Relations between the two countries have been particularly strained recently. Luis Felipe Rios Castaño, a Colombian national, pled guilty to charges of espionage last month in the Nicaraguan capital of Managua after authorities followed him for over a year. The country's prosecutor general requested a 17 year sentence for the spy on Tuesday.