The Japanese government has summoned the Chinese ambassador to protest the presence of four Chinese maritime surveillance ships for half a day near disputed islands in the East China Sea.

The islands, called Senkakus in Japanese and Diaoyu in Chinese, are controlled by Japan but also claimed by Beijing and Taiwan.

Deputy Foreign Minister Akitaka Saiki called Ambassador Cheng Yonghua to the Foreign Ministry Tuesday after the four Chinese government ships remained in waters off the islands for about 13 hours Monday until just after midnight early Tuesday, said Masaru Sato, a ministry official.

Tensions over the tiny, uninhabited islands have spiked after Tokyo purchased the islands from their Japanese private owners in September, prompting Chinese to hold demonstrations and boycott Japanese products.