Beijing has a new ship capable of creating artificial islands — potentially the largest of its kind in Asia — raising fears it could be deployed in the tension-laden South China Sea.

The world’s second-largest economy is testing a new deep sea dredger, an excavation vessel used for land reclamation, state-run media recently reported. The 140-meter-long Tian Kun Hao is capable of gathering 6,000 cubic meters of sand per hour from 35 meters beneath the sea and moving it away to create new land features, according to propaganda outlet Global Times.

China has many land reclamation projects along its coastlines, so the presence of a new dredger isn’t unusual. But the nation’s track record of territorial aggression has spurred concerns the device will be used to create man-made islands in the South China Sea.

Beijing has previously utilized dredgers to create seven fortified islands — some of which now house airfields, missile bases and radar systems — in the international waterway. That happened despite contesting assertions of sovereignty from Vietnam, the Philippines, Malaysia, Brunei and Taiwan. Chinese President Xi Jinping’s administration relies on a concept known as the nine-dash line to mark territorial claims, which extend roughly 1,000 miles from the nation’s southern shores.

“Given the strategic importance of the South China Sea islands and the extent of their recent development it would certainly be reasonable to suspect that this dredger might be used there,” said Duncan Innes-Ker, Asia regional director at The Economist Intelligence Unit.

Map courtesy of Stratfor

Just last week, satellite imagery showed evidence of more Chinese-led construction and reclamation in the disputed area, Reuters reported.

The new dredger, expected to go into service next year, isn’t designed to stir up trouble, Chinese Foreign Ministry spokesperson Hua Chunying said on Wednesday. But South China Sea claimants are wary.

“The mere presence is a little bit concerning,” Philippine Defense Secretary Delfin Lorenzana was quoted by local media as saying. “Where it is going, we do not know … We are constantly monitoring the movement of the ship.”

The new dredger, currently conducting patrols, is more powerful than previous ones used in the South China Sea, noted Bonnie Glaser, senior Asia advisor at the Center for Strategic and International Studies.

“Eventually, the Chinese might dredge more,” she warned, adding that it would likely occur after Beijing deploys military assets such as aircraft and navy ships to existing islands.

The development comes amid a period of relative calm in the strategically important region.

Beijing said it recently reached separate agreements with Manila and Hanoi, two of the most vocal claimants, to peacefully manage disputes and refrain from occupying new land features. Abiding by that deal, Philippine President Rodrigo Duterte recently halted construction on a new sandbar in the Spratly Islands, which both Beijing and Manila lay claim to, following complaints from Xi’s administration.

Southeast Asian foreign ministers and Beijing are now expected to negotiate on a code of conduct for the area.

Some analysts warned against reading too much into the new dredger.

“These kind of ships can be used for legitimate engineering projects,” said Ian Storey, senior fellow at the ISEAS-Yusof Ishak Institute, a Singapore-based think tank.

Creating new land features wouldn’t be in Beijing’s interests, he continued. Territorial tensions have cooled recently so signs of aggressive behavior “would bring a complete stop to positive momentum,” he said. “There’s no obvious advantage for China to do so.”