New photographic evidence has emerged of "significant" Chinese military defences on artificial islands in the South China Sea, a think tank reports.
China had previously committed to not militarising its controversial developments in the region.
But satellite images published by a US group appear to show anti-aircraft guns and missile defence systems on the seven islands.
Several countries claim territorial rights in the South China Sea.
In a report on Wednesday, the Asia Maritime Transparency Initiative (AMTI) said it had been tracking construction of hexagon-shaped buildings on four of the Spratly islands for several months.
Read more at BBC.