Context:

The US has withdrawn an invitation for China to participate in a multinational naval exercise the U.S. is hosting this summer, a sign of fresh tension between Pacific powers.

Background:

• The U.S. had included China the past two years in the large-scale exercise known as Rim of the Pacific, or RimPac, as part of an effort during the Obama administration to stabilize military relations with Beijing, which have been disrupted many times by China’s objections to U.S. arms sales to Taiwan.

Recent Issues:

• A Pentagon statement said the decision to disinvite the Chinese navy was “an initial response” to what it called China’s militarization of the South China Sea. 
• The Pentagon cited what it called strong evidence that China has deployed anti-ship missiles, surface-to-air missile systems and electronic jammers to contested areas in the Spratly Island region of the South China Sea. It called on China to remove these systems.
• China’s continued militarization of disputed features in the South China Sea only serve to raise tensions and destabilize the region
• The Pentagon also cited its objections to China’s recent landing of bomber aircraft at Woody Island.

About RIMPAC:

• RIMPAC, the Rim of the Pacific Exercise, is the world’s largest international maritime warfare exercise. RIMPAC is held bienniallyduring June and July of even-numbered years from Honolulu, Hawaii.
• It is hosted and administered by the United States Navy’s Pacific Fleet, headquartered at Pearl Harbor, in conjunction with the Marine Corps, the Coast Guard, and Hawaii National Guard forces under the control of the Governor of Hawaii.
• The US invites military forces from the Pacific Rim and beyond to participate. With RIMPAC the United States Pacific Command seeks to enhance interoperability between Pacific Rim armed forces, ostensibly as a means of promoting stability in the region to the benefit of all participating nations.
• Several observer nations are usually invited, including China, Ecuador, India, Mexico, the Philippines, and Russia. While not contributing any ships, observer nations are involved in RIMPAC at the strategic level and use the opportunity to prepare for possible full participation in the future.

Source:TH & Wiki