Hong Lei, Foreign Ministry Spokesperson, holds a regular press conference on January 11, 2016. (Photo from official website of China's Ministry of Foreign Affairs)

The Vietnamese accusation claiming that China's test flights to the newly built airport on Yongshu Jiao affected regional security does not hold water, said a spokesperson of China's Foreign Ministry at a press conference Monday, adding that China had informed the Vietnamese side of the flight plan in advance.

The director of the Civil Aviation Authority of Vietnam said that Vietnam had sent letters of protest to China and the International Civil Aviation Organization (ICAO), saying that Chinese aircraft have ignored all the rules and norms of the ICAO by flying across Vietnam's airspace over the South China Sea without providing any flight plans or maintaining any radio contact with Vietnam's air traffic control center, which threatens regional air safety.

In response to Vietnamese claim, Hong Lei, a spokesperson of China's Foreign Ministry reiterated that China has indisputable sovereignty over the Nansha Islands and their adjacent waters. China's inspection and test flights to the newly built airport on Yongshu Jiao fall completely within China's sovereignty.

"It is utterly untrue that Vietnamese side said about China not providing any flight plans or maintaining any radio contact with Vietnam's air traffic control center and threatened regional air safety," said Hong.

Hong pointed out that what the Vietnamese side said about China not notifying it is utterly untrue. On Dec. 28, 2015, the Flight Inspection Center of the Civil Aviation Administration of China informed the Ho Chi Minh Flight Information Region of the flight plan, route and other technical information concerning China's inspection aircraft in accordance with relevant regulations and international practices. However, up until now, the Vietnamese side has not given any response.

Besides the aforementioned notifications by competent authorities, the Chinese side also made specific contact with the Vietnamese diplomatic authorities on Dec. 30 for technical notification and explanation, Hong added.

"It is regrettable that the Vietnamese side, failing to see the professional, technical and civil nature of China's inspection and test flights which are conducted for public interest, continues to obstruct China's normal activities for no reason."

To ensure safe and effective inspection and test flights, the Chinese government decided that the flights would be conducted by civil aircraft as state aviation activities. As stipulated by international law, state aviation activities, not bound by the Convention on International Civil Aviation and relevant regulations of the ICAO, are within sovereign states' independent hands to operate, Hong said.

The spokesperson added that the Chinese side independently, safely and successfully completed inspection and test flights to the newly-built airport on Yongshu Jiao. The results showed that the airport completely meets the standards for civil aviation and is fully capable of guaranteeing safe flight of civil aircraft. It will provide a convenient means of transportation for personnel exchanges and emergency aid and enable the South China Sea region to better offer public services including maritime search and rescue.