Japan has promised to launch an investigation after it claimed that several Chinese warships and a number of submarines were seen in international waters, it has been reported.
Defense minister for Japan Toshimi Kitazawa said the country will conduct "a detailed analysis" and try and deduce whether there was "any intent" towards Japan on China's part, said news agency AP.
The boats and submarines were seen in the waters off the southern island of
Okinawa, Japan said.
The source noted that there have been a number of other similar incidents in recent years. Last week, a Chinese helicopter flew within 300 feet of a Japanese vessel, according to a Japanese spokesperson from the defense ministry.
Since 2008, there have been three incidents where Chinese ships have been spotted in the waters, they said.
Tokyo is currently waiting for a response to a request for information about the helicopter incident, the spokesperson went on to say.
China and Japan have traditionally had strained relations but the nations are each others largest trading partner.
Written by Mark Smith.
Related news stories:Okinawa bird under threat from cars (8th November 2011)Japanese workers take just 8 days off a year (3rd September 2008)What's happening in Tokyo this October? (24th September 2008)Japanese scientist scoops Nobel Prize (9th October 2008)