The Center for Strategic and International Studies said in a report late Wednesday that the anti-aircraft guns and close-in weapons systems designed to guard against missile attack have been placed on all seven of China's newly created islands.
The outposts were built in recent years by piling sand on top of coral reefs followed by the construction of airstrips, barracks, lighthouses and radar stations and other infrastructure.
China says the islands are intended to boost maritime safety in the region. They also mark its claim to ownership of practically the entire South China Sea, its islands, reefs and other maritime features.
The US has committed to beefing up its military presence in the area, although new uncertainty has been introduced by incoming US president Donald Trump.
The president-elect has called for a reconsideration of its commitments to its Asian allies, including Japan and South Korea, while simultaneously criticizing Chinese trade policy toward the US and its new territorial assertiveness.
Trump referred to China's man-made islands in a tweet earlier this month, saying Beijing didn't ask the US if it was OK to "build a massive military complex in the South China Sea.