Santiago, Chile ? Chile received two U.S. warplanes Tuesday out of 10 it had ordered from the United States as part of a major military upgrade that has worried some of its South American neighbors.

Chile ordered the F-16s in 2002 after the U.S. ended a 20-year ban on the sale of high-tech weaponry to Latin America. The F-16s are not equipped with advanced air-to-air missiles in keeping with a U.S. policy against introducing new military technology to a region. Authorities did not say which missiles the planes carried.

Despite fears from some of Chile’s already-weaker neighbors, President Ricardo Lagos insisted that Chile is not altering the region’s military balance.

“What we are doing is just replacing material that has completed its useful life,” Lagos said at a reception ceremony for the first two fighter planes at a military airport near Santiago.