The Philippines has formally protested to China against what it says is the reinforcement of Chinese posiitons on a reef in the disputed Spratly Islands in the South China Sea.

The Philippine Defence Secretary Orlando Mercado told the BBC that he thought the Chinese were trying to restate their claim that the entire South China Sea was, as he put it, a Chinese lake.

China maintains that its structures on the disputed reef are fishermen's shelters with no military purpose.