The United States warned China against any plans of adding a nuclear element to the ongoing territorial controversy in the South China Sea after a report claimed Beijing will likely construct floating nuclear power plants on disputed islands and reefs.

“China’s plans to power these islands may add a nuclear element to the territorial dispute,” the Pentagon said in its 2018 report to Congress titled “Military and Security Developments Involving the People’s Republic of China.”

“China indicated development plans may be underway to power islands and reefs in the typhoon-prone South China Sea with floating nuclear power stations; development reportedly is to begin prior to 2020," the report, released Thursday, added. 

There have been reports in the past about China's plans of building up to 20 floating nuclear plants to “speed up the commercial development” of the South China Sea.

Last year, several Chinese state-run companies formed a joint venture aimed at strengthening China’s nuclear power capabilities in line with its ambitions to “become a strong maritime power,” the South China Morning Post said, citing a statement released by the venture.

China claims most of the South China Sea, through which over $3.4 trillion of maritime trade passes annually. Brunei, Malaysia, the Philippines, Indonesia and Taiwan also have conflicting claims to the waters. According to the U.S. Energy Information Administration, it is estimated that 11 billion barrels of oil and 190 trillion cubic feet of natural gas sit below the surface of the South China Sea.

Tensions between the U.S. and China have also escalated over the ongoing dispute, with the Trump administration in May revoking an invitation for Beijing to join in Pacific naval exercises due to its activities in disputed parts of the sea.

“As an initial response to China’s continued militarization of the South China Sea we have disinvited the PLA Navy from the 2018 Rim of the Pacific” exercises, Lieutenant Colonel Christopher Logan, a Pentagon spokesman, said in a statement at the time.

“We have strong evidence that China has deployed anti-ship missiles, surface-to-air missile systems, and electronic jammers to contested features in the Spratly Islands region of the South China Sea,” Logan said in the Pentagon statement. “China’s landing of bomber aircraft at Woody Island has also raised tensions.”

“China’s continued militarization of disputed features in the South China Sea only serve to raise tensions and destabilize the region,” Logan added.