Story highlights China conducts test flight from airstrip in South China Sea

Vietnam says considers action serious infringement

Hong Kong (CNN) China has defended conducting a test flight on a newly built airfield on reclaimed land in disputed waters in the South China Sea after objections from Vietnam.

Hua Chunying, China's foreign ministry spokesperson, said Saturday that a civilian aircraft used by the Chinese government conducted a test flight at the new airport on Fiery Cross Reef in the Spratly Islands.

Hua said the activity is "entirely within the range of China's sovereignty concerns."

Vietnam's Ministry of Foreign Affairs said it considered the action a serious infringement of the sovereignty of Vietnam on the Spratly Islands and asked China to not to repeat the flight.

Japan also expressed concern Monday, with Foreign Minister Fumio Kishida saying such acts "don't contribute to the peaceful settlement of the dispute" and "should be avoided."