Twenty nations — including China — sent representatives in May to the first planning conference for 2014 Rim of the Pacific war games off Hawaii, which the Navy said could be bigger than ever next summer.

"We had 22 nations … in the last one," Chief of Naval Operations Adm. Jonathan Greenert said last week. "We think this one could be bigger."

After RIMPAC ended last year, the U.S. asked China to participate in 2014 after equivocating over whether to invite the Asian nation, whose rapidly growing military, and its intentions in the region, are high on the Pentagon’s list of worries.

A total of 22 nations, 25,000 personnel, 40 ships, six submarines and more than 200 aircraft participated in the big joint exercise June 29 through Aug. 3, 2012, in and around Hawaii.

So many nations were involved that China complained it felt left out.

"Watching from afar, China is feeling uncomfortable," the Global Times, published under the auspices of the Communist Party of China, said at the time.

There remains plenty of discomfort on both sides.

China has vexed the United States and its partners in the region with territorial claims to the South China Sea and maritime spats with Japan and the Philippines.

It corralled the U.S. surveillance ship USNS Impeccable in 2009, which was searching for submarines, and last month told the ship — sailing in international waters — that it was operating without China’s permission.

The Pentagon said Chinese naval activity now is occurring in the 200-nautical mile Exclusive Economic Zones around Hawaii and Guam — the same thing that China has complained the U.S. is engaging in off China’s coast.

The United Nations Convention on the Law of the Sea defines territorial waters as extending 12 nautical miles from shore.

Greenert pointed to RIMPAC as a source of engagement with China, and said he’ll be meeting with his Chinese navy counterpart, Adm. Wu Shengli, in September.

"And we agree," Greenert said, "we need a protocol at sea to be comfortable, talking to each other, interoperating when appropriate and when it makes sense, and understanding that these territorial disputes have to be done peacefully, and we’ve got to eliminate miscalculation."

The RIMPAC initial planning conference — one of three — was held at Naval Base Point Loma, Calif., May 28-31. The U.S. 3rd Fleet, headquartered in San Diego, runs RIMPAC.

Representatives from Australia, Brunei, Canada, Chile, Colombia, France, Indonesia, India, Japan, Malaysia, Mexico, New Zealand, Norway, China, Peru, South Korea, Russia, Singapore, Thailand and the United States attended the conference, the Navy said.

During the conference, participating nations were given an opportunity to provide their training objectives to the planning group to determine the design of the exercise.

The biennial exercise adds millions to the coffers of Oahu hotels, restaurants and bars, mostly at the beginning and end of the war games when the ships are in port.

How the exercise will be bigger in 2014 and what China will bring to it are still unclear.

"As planning for the exercise is still in the very early stages, it would be premature to discuss which units each nation will bring or specific training events in which they will participate," said Lt. Lenaya Rotklein, deputy public affairs officer for the 3rd Fleet.

China objects to U.S. Navy activities within its EEZ, while the United States considers passages through all nations’ zones to be lawful.

In a 2013 annual report to Congress on China military and security developments, the U.S. Defense Department said the People’s Liberation Army Navy has begun to conduct military activities within the EEZs of other nations without the permission of those coastal countries.

"Of note, the United States has observed over the past year several instances of Chinese naval activities in the EEZ around Guam and Hawaii," the report states.

One of those instances was during RIMPAC 2012.

"While the United States considers the PLA Navy activities in its EEZ to be lawful, the activity undercuts China’s decades-old position that similar foreign military activities in China’s EEZ are unlawful," the Defense Department said.

Adm. Samuel Locklear III, the head of U.S. Pacific Command, said in June that China had started "reciprocating" the U.S. practice of sending ships and aircraft into the 200-nautical-mile zone off China, the Financial Times reported.

Locklear said he had no problem with China entering U.S. EEZs, the news organization said.

John Pike, director of Virginia-based think tank GlobalSecurity.org, said the Chinese naval forays around Hawaii — possibly for intelligence purposes — are "no big deal."

"What is it that they might learn that is going to be a problem for us?" Pike said. "I can’t think of anything."

Pike said the incursions into U.S. EEZs are significant "in terms of China going further afield — China emerging as a blue-water navy."

In June, the U.S. surveillance ship Impeccable was challenged by a Chinese maritime ship in what a video of the encounter describes as the East China Sea.

The Impeccable was radioed by Chinese officials and told that it shouldn’t be operating "without the permission of the Chinese government."

The U.S. Navy 7th Fleet issued a statement Wednesday saying: "The two ships were operating in international waters beyond the territorial seas of any nation. The navigation and maneuvers of the two ships were conducted in a safe and professional manner in accordance with international norms, standards, rules and laws."

Pike said China’s maritime claims in the region are a potential flashpoint for conflict.

"The Chinese have got some extremely peculiar views about who owns the South China Sea, and if there’s any point at which America and China can have a military collision — that is it," Pike said.