Worrying new satellite imagery suggests China is building "full-blown military bases" on controversial artificial islands in the South China Sea.
A report by geospatial software company Simularity has revealed what appears to be infrastructure for radars, antennae mounts and what could be a potential military base on Mischief Reef.
Classified as an atoll – a ring-shaped coral reef – located 250km from the Philippines, the landmass has been occupied and controlled by the People's Republic of China since 1995.
The images show the construction in seven areas between May 2020 and February 2021.
One image dated May 7, 2020 clearly shows an empty plot of space, which is now occupied by a 16 metre-wide cylindrical structure which Simularity claims could be a "possible antennae mount structure".
Another shot also shows a concrete structure with a spherical radome – a weatherproof enclosure used to protect a radar antennae – cover nearby. Simularity states this could "possibly be a fixed radar structure".
Other sites are still mid-construction or have been cleared for further development.
Dr Jay Batongbacal, Director of the Institute for Maritime Affairs Law of the Sea in the University of the Philippines, says the new infrastructure suggests China is digging in.
"They're basically adding on survey lens equipment, apparently radars – there's already a lot of them in the reef in the first place," he told Philippine broadcaster ANC.
"The addition of new radars appears to indicate they're really expanding the capabilities of this artificial island. And then the fact it is continuing despite everything that has been going on in the rest of the world, it really indicates the intention of China to really fully develop these artificial islands into full-blown military bases."
This isn't the first time Mischief Reef has been at the centre of geopolitical tensions in the area.
A 2016 ruling by the Permanent Court of Arbitration in The Hague ruled that Mischief Reef is within the exclusive economic zone of the Philippines.
The relationship between the two countries remains turbulent.
In January 2021, Beijing passed the Coast Guard Law, or the "open fire": law, which gave their navy and coast guard the power to take all necessary measures to defend its sovereignty in the disputed waters.
Speaking to local media, Philippines Foreign Affairs Secretary Teodoro Locsin Jr said should an incident occur, the Philippines would retaliate.
"If there is an incident, I can assure you there will be more than just a protest," he said.
The role of the United States and its tumultuous relationship with China, and allegiances with countries including the Philippines and Taiwan, also come into play.
In the event of an armed attack the superpower has committed to defending the Philippines in an effort to temper China's aggressive fight for control in the area.
Reiterating America's support for the South East Asian country, State Department spokesman Ned Price said new Secretary of State Antony Blinken rejected "China's maritime claims in the South China Sea".
"The United States rejects China's maritime claims in the South China Sea to the extent they exceed the maritime zones that China is permitted to claim under international law as reflected in the 1982 Law of the Sea Convention," he said.
"Secretary Blinken stressed the importance of the mutual defence treaty for the security of both nations, and its clear application to armed attacks against the Philippine armed forces, public vessels or aircraft in the Pacific, which includes the South China Sea."