BEIJING -?China's refitted aircraft carrier left its shipyard on Wednesday morning to embark on its first sea trial.

Military sources said that the first sea trial was in line with schedule of the carrier's refitting project. After returning from the sea trial, the aircraft carrier will continue refit and test work.

Before China, a total of nine countries are in possession of aircraft carriers, including the United States, the United Kingdom, France, Italy, Spain, Russia, India, Thailand and Brazil.

Among the five permanent members of the United Nations Security Council, China is the last one possessing an aircraft carrier platform.

The possession of the vessel is vital to China, as the country has vast territorial waters, which induces grave responsibility of protection.

China has more than 18,000 kilometers of coast line and three million square kilometers of territorial waters. From the Opium War in 1840 to the founding of the People's Republic of China in 1949, China suffered more than 470 offenses and invasions that came from the seas.

The establishment and expansion of the People's Liberation Army (PLA) navy have significantly improved the country's maritime defense. However, restrictions in economic strength and scientific research have long prevented China from modernizing its navy.

The PLA navy's current defense capability is still disproportionate to the requirements of its missions.

With the expansion of globalization and its ever-expanding openness to the outside world, China's national interests have become increasingly interconnected with that of the whole world.

China, with long and busy sea lanes to secure for the flow of materials and manufactured goods in and out of the country, is entitled to a modernized fleet.

Apart from its need for national defense, an improved navy force will better serve China' s purpose of international cooperation against maritime crimes.

Chinese navy fleets had by June escorted 3,953 ships from countries all over the world through the Gulf of Aden and waters off Somalia, among which 47 percent were foreign commercial ships.

Refitting Varyag is seen by many people as China's distinctive way of developing an aircraft carrier. But it will be a lengthy process from the sea test to the shaping of combat prowess. As military experts said, Varyag is only a platform for scientific research, experiments and training.

China's pursuit of an aircraft carrier will not change the defensive nature of the country's national defense policy or the country's independent foreign policy of peace. China calls for a harmonious world and a harmonious ocean.

Developing an aircraft carrier will buttress the country's economic development in a strategically important period and its distinctive path of peaceful development.

There should be no excessive worries or paranoid feelings on China's pursuit of an aircraft carrier, as it will not pose a threat to other countries, and other countries should accept and be used to the reality that we are developing the carrier.