HONG KONG — China may be building a series of radar facilities on artificial islands in disputed waters in the South China Sea, which would help it to establish “effective control” over sea and air in one of the world’s busiest waterways, according to a report issued this week.

The report, released on Monday by the Center for Strategic and International Studies in Washington and based on satellite images taken as recently as Feb. 12, came less than a week after the United States said that China appeared to have deployed surface-to-air missiles on another disputed island.

Late Tuesday, the Pentagon said recent deployments of fighter jets to that island put China at odds with its neighbors in the region, including Vietnam and the Philippines.