Vietnam's practice of fortifying islands and reefs under its control is nothing new. Military installations and garrisons have dotted the features of the Spratly archipelago — including the Southwest Cay, Sin Cowe Island and Spratly Island itself — for some time. But over the past two years, Vietnam has redoubled its efforts to reclaim and build up these islets and reefs, creating over 50 hectares (120 acres) of new land in the archipelago in spite of U.S. calls for it to stop so as to avoid escalating tensions in the sea. Vietnam Engineers a Deterrent Based on satellite imagery, Vietnam's latest projects on Spratly Island include the extension of a 600-meter (2,000-foot) runway to 1,200 meters and the construction of two large hangars, in addition to the two that already existed. Once these projects are finished, the island will be able to accommodate most of the Vietnamese air force's aircraft.