China has completed the initial phase of land reclamation at Antelope Reef in the disputed Paracel Islands, according to satellite images examined by Reuters.

The images reportedly show the outline of a newly created artificial feature after at least six months of dredging and construction. Barges and dredging vessels involved in the operation have since left the site.

The Paracel Islands are controlled by China but are also claimed by Vietnam and Taiwan. Their location in the South China Sea gives them strategic importance for shipping, military surveillance and regional security.

It has not been independently established what permanent facilities China intends to build at the site. Analysts nevertheless believe further construction could strengthen Beijing’s ability to monitor and operate in the surrounding waters.