China says it is to conduct a survey of disputed East China Sea islands, amid a bitter diplomatic row with Japan.
State news agency Xinhua said the survey was part of China's "programme to safeguard its maritime rights and interests".
The island are called Diaoyu in China and Senkaku in Japan.
The row over the islands, which are controlled by Japan, has left ties between Tokyo and Beijing highly tense.
Xinhua said the survey was the second part of a programme to map China's territorial islands and reefs, after the first part was completed in 2009.
"The second stage will cover islands including the Diaoyu Islands," the report said, citing the National Administration of Surveying, Mapping and Geoinformation.
It did not expand on how and when the survey work would take place.
Fighters and ships
The row over ownership of the islands, which lie south of Okinawa and north of Taiwan, has been rumbling for years.
It reignited in September when the Japanese government purchased three of the islands from their private Japanese owner, leading to protests in some Chinese cities and fall-out for some Japanese businesses operating in China.
Chinese government ships have since sailed many times through what Japan says are its territorial waters around the islands.
Late last year, a Chinese government plane also overflew the islands in what Japan called a violation of its airspace. Japanese fighters have been scrambled on a number of occasions since then.
New Japanese Prime Minister Shinzo Abe, who was elected in December, has pledged a tough stance. He says the issue of ownership is not up for negotiation but has also called for more dialogue with Beijing.
Last week it was announced that Japan planned to increase military spending for the first time in a decade - albeit by a small amount - in a move that has been linked to the row with China.
Japan also appears to be looking to reinforce its capabilities in the area - public broadcaster NHK reported on Monday that two more patrol ships will be deployed to the area later in the year.
Kyodo News agency, citing unidentified government sources, said on Tuesday that defence officials were looking into basing fighter jets closer to the disputed island chain, utilising a runway on a small island south of Okinawa.
The top US East Asia diplomat, Kurt Campbell, is due in Japan later in the week for talks expected to include the territorial row, on which Washington has urged both sides to exercise caution.
Former Japanese leader Yukio Hatoyama is also in Beijing on a private visit.
Mr Hatoyama, whose Democratic Party is now in opposition after December's election, has in the past called for Japan to improve its ties with Beijing in a rebalancing of traditional alliances.
Local media report he is seeking talks with Chinese leaders.