Tuesday, August 16, a Chinese research vessel entered Sri Lanka's Chinese-run southern port of Hambantota, despite India and the United States' concerns about its activities.
The Yuan Wang 5 visited the deep sea port of Hambantota after receiving permission to enter Sri Lankan waters on the condition that it would not conduct any research, according to port officials.
The vessel was scheduled to arrive last week, but Colombo asked Beijing to postpone the visit in response to complaints from India, which shares Western concerns over Chinese actions in the region.
Last Saturday, however, following intense talks, Colombo announced that permission had been obtained for the ship to land at Hambantota for a six-day stay.
The Yuan Wang 5 was classified as a research and survey vessel on shipping analytics websites, but according to Indian media, it is a dual-use surveillance ship.
New Delhi views Beijing's growing presence in the Indian Ocean and influence in Sri Lanka with suspicion, which considers both to be firmly within its sphere of influence.
A day before the ship's arrival, India presented Sri Lanka with a Dornier 228 surveillance aircraft to enhance the island's maritime surveillance capabilities.
The Chinese ship was permitted to enter the Sri Lankan seas because it maintains its Automatic Identification System (AIS) and refrains from scientific research.
China leased the Hambantota port for 99 years for US$1.12 billion (S$1.54 billion), less than the US$1.4 billion Sri Lanka paid a Chinese company to construct it.
According to Indian reports, the Yuan Wang 5 might be used for satellite and space tracking and has specific applications for intercontinental ballistic missile launches.
The Indian government has complained to Colombo, fearing the ship could eavesdrop on its activities. The United States also voiced alarm regarding the boat.
After falling behind on debt repayments between 2005 and 2015, Sri Lanka surrendered its lease on the Hambantota port, located on the main East-West shipping lanes, to China in 2017.
China remains Sri Lanka's largest bilateral creditor, holding more than 10% of the island's foreign debt.
Colombo, experiencing a terrible economic crisis, needs Beijing's assistance to restructure its external debt to qualify for a bailout from the International Monetary Fund.
President Ranil Wickremesinghe "reiterated Sri Lanka's firm commitment to the one-China policy" on August 4 in response to US House Speaker Nancy Pelosi's visit to Taiwan, during which she warned against "non-interference in the internal affairs of countries."