China Navy to BBC: 'Stay away from islands'

Countries from around the world have insisted that China's expansion into the South China Sea is illegal.

It is building a huge artificial island in the Spratly Island chain, one of the most contested areas in the world.

The islands are difficult to reach, but BBC correspondent Rupert Wingfield-Hayes flew in a small civilian aircraft into China's self-declared security zone, 140 miles off the coast of the Philippines.