BEIJING -- China told the Philippines and Vietnam on Wednesday to halt all intrusive action on China-owned islands in the South China Sea, following its rejection of concerns voiced by ASEAN.

Some reports said the chairman's statement at the 26th ASEAN Summit, which expressed concern over China's activities on the islands, ignored the large-scale reclamation and military buildup by certain ASEAN members in the South China Sea.

Defending China's building activities, Foreign Ministry spokesperson Hong Lei on Tuesday said China's construction activities on the Nansha Islands are within the scope of China's sovereignty, which is unimpeachable.

The Philippines and Vietnam are illegally occupying islands and reefs that are part of China's Nansha Islands, where they have built fixed facilities like airports, reclaimed land and even deployed offensive weapons like missiles, Hong told reporters on Wednesday.

"China expresses grave concern and strong opposition to these illegal activities," Hong said, urging relevant countries to "immediately stop all action and words that infringe upon China's sovereignty and interests."

The Philippines has built an airport and dock on Zhongye Dao, Nansha Islands, while constructing tourism facilities there and on another two islands, Mahuan Dao and Feixin Dao, according to Hong.

The Philippines' stranded warship near the Ren'ai Reef has served as a permanent installation since 1999 in an attempt to seize the reef, he said.

Vietnam has undertaken large-scale reclamation work on more than twenty islands and reefs belonging to Nansha Islands, building ports, runways, missile positions, office buildings, camps, hotels and lighthouses, the spokesperson said.

Vietnam has also built a number of houses and helicopter platforms on Wan'an Tan, Xiwei Tan, Lizhun Tan and Aonan Ansha, Hong added.