Peru's Foreign Minister Jose Garcia Belaunde said on Wednesday that Peru is concerned about Chile buying eight U.S. F-16 warplanes.
"The purchase of this fleet affects the region's strategic and military balance," he said. He added that two F-16s are based in Chilean military base Iquique, near the Peruvian border.
"We have already expressed our concern about this massive arms purchase," Garcia said, adding that it was particularly worrying to see this build-up when the two nations are trying to make their military spending match more closely.
He said the purchase would be discussed in the next 2+2 Meeting, that brings together Chile and Peru's defense and foreign ministers.
Relations between the two countries have been difficult and remain scarred by a 1879-1884 war won by Chile that annexed some Peruvian territory. Peru has said it will seek adjudication at international tribunals based in The Hague.