Image copyright AFP Image caption Japan's Prime Minister Shinzo Abe (C) has approved defence spending rises

Japan's defence ministry has made its biggest ever budget request, amid severe tensions with China over a maritime dispute in the East China Sea.

The ministry is seeking 5.05 trillion yen (£29.4bn; $48.7bn) for the year - a 3.5% rise.

If approved, it would mark the third year the defence budget had been increased, after a decade of cuts.

Earlier this month, the ministry described the security environment around Japan as "increasingly severe".

Beijing and Tokyo are engaged in a bitter dispute over islands known as Senkaku in Japan and Diaoyu in China.

In its annual white paper, the ministry spoke of "great concern" over China's activities in the East China Sea and also cited North Korea as a security threat.

According to its budget request, the ministry wants to purchase 20 maritime patrol aircraft.

It also wants to buy five crossover aircraft, which have both airplane and helicopter functionalities, three drones and six stealth fighters.

"It is not a sudden increase in defence equipment for us, but rather a typical necessity in the process of keeping up with the maintenance of the Japanese defence system," said Defence Minister Itsunori Onodera at a budget meeting, according to the Associated Press.

Image copyright AP Image caption Under its constitution, Japan cannot use force to resolve conflicts except for self-defence

Image copyright Reuters Image caption The disputed East China Sea islands are claimed by both Japan and China

Earlier this week, Kyodo news agency reported that Japan's Coast Guard had requested a doubling of its current budget to 50.4bn yen, amid plans to acquire more patrol vessels and increase patrol personnel.

Jiji Press said it also planned to construct a large patrol ship for a security unit specifically for the disputed islands.

The islands are controlled by Japan. But since the Japanese government purchased three of them from their private Japanese owner in 2012, a long-simmering row over their ownership has escalated dramatically.

Chinese boats and aircraft have since been patrolling in and out of what Japan says are its territorial waters, prompting fears of a clash.

Media playback is unsupported on your device Media caption BBC's Laura Westbrook reports

Japanese Prime Minister Shinzo Abe, who took power in December 2012, has been more assertive in boosting Japan's military.

Under its pacifist constitution, Japan is barred from using force to resolve conflicts except for self-defence.

But in July Japan's cabinet approved a landmark change that paves the way for its military to fight overseas. The government has also eased curbs on weapons exports.

The defence ministry budget request will now be the subject of negotiations with government spending chiefs before the full budget is compiled at the end of the year.

China has seen a sharp increase in its official defence budget, which is more than two and half times larger than Japan's.

The US has by far the world's largest military budget, spending $600bn on defence last year.