Boats carrying Japanese politicians and activists have moored off a group of disputed islands, amid protests by China which claims them for its own.

Some 150 Japanese, most of them nationalists, are on the boats at the Senkaku islands, called Diaoyu in China, which are under Japan's control.

They want to commemorate Japanese dead in World War II, despite being denied permission to go ashore.

China says the event will undermine its territorial sovereignty.