In recent weeks, Chinese and Vietnamese ships have repeatedly seen clashes like this one in disputed waters in the South China Sea. In the sky, planes from Japan and China have had near brushes, with each blaming the other.
Anti-China protests are spreading. Residents in the Philippines recently took to the streets. Protestor Marimi Dela Fuente was with them. "China is infringing upon our sovereignty. That is why I am here to rally our citizens against China's abuses to the world, and our country and to Southeast Asia," Fuente said.
And it is not just China's neighbors that are concerned. U.S. Secretary of Defense Chuck Hagel recently accused China of taking destabilizing unilateral actions to assert its territorial claims in the South China Sea.
In the past, Beijing may have shied away in the face of such mounting criticism. But its decision to participate in RIMPAC, shows a willingness to be more transparent and highlights the growing maturity of military ties with Washington, said Peking University political scientist Wang Dong.
"Certainly there is a big substantive perception gap between China and the United States and its allies, and it is very important to narrow those perception gaps and I think the best way to do that is through communications and exchanges," said Dong.
The United States has long been a leader in the Pacific, but with growing budget constraints at home and China's rapid rise, the two are adapting to a new situation and growing pains are to be expected, says Lin Chong-Pin, a former deputy defense minister in Taiwan. He spoke to VOA via Skype. "Both are looking for a new relative position. And during this period of testing and adjustment there are pains and that is what we are seeing," he explained.
But Beijing's toughness has limits, Lin argued. He said part of the reason why China is raising tensions with its neighbors is because China's President Xi Jinping cannot appear weak to the outside world. "In order to go forward on reform he needs protection, because these reforms will affect the vested interests of a lot of powerful people in the government and outside the government," Lin noted. "Therefore, he cannot afford to appear weak to the domestic audience.
China has sent sent four ships to the month long drills -- a missile destroyer, missile frigate, a supply ship, and its hospital ship the Peace Ark. During the drills, more than 1,000 Chinese sailors and officers will rub shoulders with their counterparts from more than 20 other countries.