Satellite photographs taken in late July show China appears to have built reinforced aircraft hangars on its holdings in disputed South China Sea isletss, a Washington-based research group said.

The hangars on Fiery Cross, Subi and Mischief Reefs in the Spratly islands have room for any fighter jet in the Chinese air force, the Center for Strategic and International Studies (CSIS) said in a report on the photographs.

The images have emerged about a month after an international court in The Hague ruled against China's claims in the resource-rich area, a decision rejected by Beijing. China claims most of the South China Sea, through which $5 trillion in ship-borne trade passes every year. The Philippines, Vietnam, Malaysia, Taiwan and Brunei have overlapping claims.