BEIJING: A report from a US think tank says China has nearly completed construction work on three man-made islands in the South China Sea, giving it the ability to deploy combat aircraft and other military assets to the disputed region whenever it wishes.

The Washington-based Center for Strategic and International Studies analyzed recent satellite photos and concluded that runways, aircraft hangers, radar sites and hardened surface-to-air missile shelters have either been finished or are nearing completion.

The report, released Monday, appears to be the most conclusive indication yet that China is using its island-building project to give teeth to its claim over almost the entire South China Sea and its islands and reefs.

The islands in the study — Subi, Mischief and Fiery Cross reefs — are part of the Spratly chain, which is claimed in whole or in part by China, the Philippines, Vietnam, Malaysia, Taiwan and Brunei.

On each of the islands, China has constructed enough concrete hangers for 24 fighter jets and four or five larger planes such as bombers or early warning aircraft, CSIS reported.

China already uses an existing airfield on Woody Island in the similarly disputed Paracel chain, located to the north, where it has maintained mobile HQ-9 surface-to-air missiles for more than a year and deployed anti-ship cruise missiles on at least one occasion, CSIS said.

The airfields and advanced surveillance and early warning radars will allow China's military to operate over virtually the entire South China Sea.

"Beijing can now deploy military assets, including combat aircraft and mobile missile launchers, to the Spratly Islands at any time," the report said.

China's creation of seven man-made islands in the South China Sea has drawn strong criticism from the US and others, who accuse Beijing of further militarizing the region and altering geography to bolster its claims.

China says its island construction is mainly for civilian purposes, particularly to increase safety for ships that carry an estimated $5 trillion worth of goods through the waterway each year. It has also provided reassurances that it will not interfere with freedom of navigation or overflight, although questions remain as to whether that includes military ships and aircraft.