The Chinese military bases constructed on artificial islands in the contested South China Sea waterway are too small, too distant from the mainland and too vulnerable to potential enemy strikes, according to a Beijing-based monthly magazine, Naval and Merchant Ships.

Published by the country’s State Shipbuilding Corporation, which builds naval vessels associated with the People’s Liberation Army, the outlet is quoted by South China Morning Post as saying the sites had an undeniable role in asserting Beijing’s claim over about nine-tenths of the South China Sea.

Certain parts of the strategic hydrocarbon and fishing resources-rich body of water, which is also home to vital shipping lanes, feature in a spate of overlapping claims from countries such as Vietnam, Malaysia, Brunei, the Philippines and Taiwan, leading to disputes with Beijing.

China has been increasingly assertive over what it insists are its centuries-old claims to the contested region, turning islands and reefs in the South China Sea into military bases and airstrips to back up those claims.

While convenient for the needs of intelligence gathering and reconnaissance, the inherent weaknesses of the bases might potentially render them defenseless if they come under attack and  they are of little use in a conflict, says the magazine.

“These artificial islands have unique advantages in safeguarding Chinese sovereignty and maintaining a military presence in the deep ocean, but they have natural disadvantages in self-defense,” the magazine said.

Firstly, the remote and isolated bases are far from the mainland, and as such, difficult to defend and supply in the event of an attack.

The magazine cites as an example the Fiery Cross Reef, where one of the bases is situated. It would reportedly take a naval support vessel 20 hours to cover the 1,000 km (600 miles) to base from the closest resupply site on Hainan island.

“Even if the support fleet rushes at the fastest speed, it will take more than a day to reach it,” the report says.