HONG KONG • Vietnam has begun dredging work on a disputed reef in the South China Sea, satellite imagery shows, the latest move by the communist state to bolster its claims in the strategic waterway.
Activity visible on Ladd Reef in the Spratly Islands could anger Hanoi's main South China Sea rival, Beijing, which claims sovereignty over the group and most of the resource-rich sea.
Ladd Reef, on the south-western fringe of the Spratlys, is completely submerged at high tide but has a lighthouse and an outpost housing a small contingent of Vietnamese soldiers. The reef is also claimed by Taiwan.
In an image taken on Nov 30 and provided by US-based satellite firm Planet Labs, several vessels can be seen in a newly dug channel between the lagoon and the open sea.
While the purpose of the activity cannot be determined for certain, analysts say similar dredging work has been the precursor to more extensive construction on other reefs.
"We can see that, in this environment, Vietnam's strategic mistrust is total... and they are rapidly improving their defences," said Mr Trevor Hollingsbee, a retired naval intelligence analyst with Britain's defence ministry. "They're doing everything they can to fix any vulnerabilities - and that outpost at Ladd Reef does look a vulnerability."
Reuters reported in August that Vietnam had fortified several islands with mobile rocket artillery launchers capable of striking China's holdings across the vital trade route.
Vietnam's Foreign Ministry did not respond to a request for comment.
The vessels at Ladd Reef cannot be identified in the images, but Vietnam would be extremely unlikely to allow another country to challenge its control of the reef.
Mr Greg Poling, a South China Sea expert at Washington's Centre for Strategic and International Studies (CSIS), said it remained unclear how far the work on Ladd Reef would go. Rather than a reclamation and a base, it could be an attempt to simply boost access for supply ships and fishing boats.
Ladd could also theoretically play a role in helping to defend Vietnam's nearby holding of Spratly Island, where a runway is being improved and new hangars built, he said.
"Vietnam knows it can't compete with China but it does want to improve its ability to keep an eye on them," Mr Poling said.
The Asia Maritime Transparency Initiative, run by the CSIS, says Vietnam has added about 49ha of land to its South China Sea holdings in recent years.
Vietnam's reclamation work remains modest by Chinese standards, however.
The United States, which has criticised China for militarising the waterway, estimates that Beijing has added more than 1,300ha of land on seven features in the South China Sea over the past three years, building runways, ports, aircraft hangars and communications equipment.