It might not have been the Philippines' intention to trigger a standoff with China over the Huangyan Island, but the Philippines' probing of China's bottom line over its sovereignty in the South China Sea has strained their relations in this sensitive issue, a diplomatic expert told China Youth Daily.

The key dispute was the Philippine navy's harassment of Chinese fishermen near the Huangyan Island in the South China Sea, said Professor Zhuang Guotu, director of the China Southeast Asian Research Association and director of the Center for Southeast Asian Studies of Xiamen University.

This was the first of such incident, Zhuang said. But the Philippines had not expected China's quick response by sending marine surveillance ships to the area to protect Chinese fishermen.

Now the Philippines are trying to take this incident as an opportunity to test China's bottom line, and that's the root cause for the current standoff between these two countries, Zhuang said.

"How to solve the dispute will be a test of the diplomatic wisdom of both sides," Zhuang said.

He pointed out that neither China nor the Philippines hopes to complicate or militarize the dispute. Both are willing to solve the incident through diplomatic talks.

The biggest question now is how to end the standoff. The longer it lasts, the more political and diplomatic pressure both sides have to face.

By April 22, the standoff had lasted for 13 days. Philippines made several moves following the incident. The Philippine government even openly announced that it would hand the Huangyan Island dispute to the International Tribunal for the Law of the Sea.

Zhuang said that the Philippines intend to take the dispute to the international court because it has nothing to lose, as the Huangyan Island does not belong to the Philippines in the first place.

The Philippines and Vietnam have been attempting to stir the South China Sea waters, Zhuang said. But they know their limited capacities, and that the U.S., Japan, India regard themselves as relevant parties in the South China Sea issue. So they choose to stick together.

Philippines and Vietnam have room for cooperation with the U.S., Japan, India and Russia. But they also have differences. "Philippines and Vietnam want to seize the sovereignty over islands or waters in the South China Sea, but the United States, Japan, India and Russia are more concerned about the free shipping," Zhuang said.