Image copyright Reuters Image caption Japan and China are embroiled in an ongoing row about disputed islands in the East China Sea

Japan has summoned the Chinese ambassador to protest against the presence of government ships in waters around disputed islands.

This is the first such protest under new PM Shinzo Abe, who was elected last month. It also comes amid reports that he wants to increase defence spending.

Chinese ships have sailed near the islands many times since Japan bought them from a private owner last year.

Both claim the islands, called Senkaku in Japanese and Diaoyu in Chinese.

The row over the islands, which are also claimed by Taiwan, has left ties between Tokyo and Beijing tense.

The dispute over their ownership has rumbled for years but the Japanese government's acquisition of three of the islands from their private Japanese owner sparked a renewed row, triggering public protests in some Chinese cities.

Japan-China disputed islands The archipelago consists of five islands and three reefs

Japan, China and Taiwan claim them; they are controlled by Japan and form part of Okinawa prefecture

Japanese businessman Kunioki Kurihara owned three of the islands but sold them to the Japanese state in September

The islands were also the focus of a major diplomatic row between Japan and China in 2010 Q&A: China-Japan islands row

Since then Chinese ships have been sailing in and out of waters around the islands, prompting warnings from Japan.

Japan's Deputy Minister for Foreign Affairs Akitaka Saiki met Chinese Ambassador Cheng Yonghua in Tokyo to lodge a protest after four Chinese government ships were spotted in the area on Monday.

Mr Saiki "strongly demanded that such incidents do not happen again", a ministry statement said.

Spending plans

The move comes amid reports that Japan could increase military spending this year for the first time in more than a decade.

A Japanese official told Agence-France Presse news agency that the Liberal Democratic Party (LDP) had decided to increase the budget request by more than 100bn yen ($1.15bn, £682.6m).

The mooted increase is not large - the defence budget for the year ending in March 2012 stood at 4.65 trillion yen ($53bn).

The official said that it would be used "for research into a new radar system" and "maintenance costs for early-warning aircraft".

The Yomiuri newspaper reported similar details.

Some of the funds would be allocated to increasing defence personnel, surveillance on the disputed islands with China and purchasing new equipment, Japan's public broadcaster NHK said on its website.

The new LDP government was elected late last year, ousting the Democratic Party government of Yoshihiko Noda.

New Prime Minister Shinzo Abe, who is known as a conservative, has pledged a strong stance on the territorial issue while also calling for dialogue with China.