China drafts plans for air defense zone in West PH Sea - Japanese news report

Beijing claims the South China Sea almost in its entirety, even areas a long way from its shoreline.

The countries surrounding the sea, among these the Philippines, have competing and overlapping claims to the area and are in dispute with Beijing, including over the ownership of islands.

Many countries, including the USand Japan, use ADIZs as a form of early warning, allowing them to track aircraft approaching their airspace.

Planes entering the area are frequently asked to identify themselves and to maintain radio contact with local authorities.

Any aircraft causing concern can trigger the launch of fighter jets, which are scrambled to intercept it.

Japan, South Korea and others reacted with anger in November when Beijing unilaterally declared an ADIZ in the East China Sea.

Chinademanded all aircraft provide flight plans when traversing the area, give their nationality and maintain two-way radio communication, or face "emergency defensive measures".

The USsaid it would not comply, and, in what was seen as a challenge to Beijing, promptly flew military planes through it.

The zone covers disputed Tokyo-controlled islands -- known as the Senkakus in Japan and the Diaoyus in China-- where ships and aircraft from the two countries already shadow each other.

Its sudden declaration bolstered claims that China is throwing its growing military weight around.

Observers say the establishment of a similar zone in the South China Sea is a likely move for Beijing.

In November the southern Chinese island province of Hainanpassed a rule requiring foreign fishing vessels to obtain permission to enter its waters, which it defined as the bulk of the sea.

In December, USSecretary of State John Kerry warned China against any move to declare an air defense zone over the sea, which is a vital transport route through which much regional and global trade passes.