The United States on Wednesday disinvited China from participating in annual maritime exercises in the Pacific in protest against Beijing’s militarisation of the South China Sea, AFP reported.

A Penatagon statement said it had “strong evidence” that China has deployed anti-ship missiles, surface-to-air missile systems and electronic jammers to the Spratly Island region of the South China Sea. Washington called on Beijing to remove these systems, AP reported.

“While China has maintained that the construction of the islands is to ensure safety at sea, navigation assistance, search and rescue, fisheries protection, and other non-military functions, the placement of these weapon systems is only for military use,” Pentagon spokesperson Lieutenant Colonel Christopher Logan said in a statement, according to The Washington Post. “China’s continued militarisation of disputed features in the South China Sea only serve to raise tensions and destabilise the region.”

The biennial military exercise, slated to begin in June, involves 27 nations in a display of international military cooperation in the Rim of the Pacific, or RIMPAC, The Wall Street Journal reported.

Several countries – China, Philippines, Vietnam, Taiwan, Malaysia and Brunei – have been fighting over the resource-rich South China Sea for years. China has claimed nearly 90% of the territory, which is defined by the nine-dash line, and has also issued a map to back its claims.

In July 2016, an international tribunal in The Hague ruled in favour of the Philippines and said Beijing had no legal basis to claim “historic rights” over the South China Sea. The Permanent Court of Arbitration accused China of breaching the sovereign rights of the Philippines by exploring resources near the Reed Bank. However, the Chinese government called the verdict “ill-founded”. Beijing also said that its “territorial sovereignty and marine rights” in the seas would not be affected by the verdict.