BEIJING China's Foreign Ministry said it would continue to take "necessary measures" to safeguard its sovereignty over a number of disputed islands in the East China Sea after Japan said it was considering a plan to "buy" them from private landowners.
The uninhabited islands, known as Senkaku in Japan and Diaoyu in China, have long been the centre of maritime territorial disputes between China and its neighbors, all of which cite historical and other claims over fishing areas and potentially rich gas deposits.
Japanese Prime Minister Yoshihiko Noda said on Saturday that the government was considering buying the islands, situated in potentially gas rich territory claimed by both Japan and China, in a move likely to anger Beijing.
"No one will ever be permitted to buy and sell China's sacred territory," Ministry spokesman Liu Weimin said in a statement issued late on Saturday on the ministry's website, www.mfa.gov.cn.
"China will continue to take necessary measures to firmly uphold its sovereignty over the Diaoyu island and its affiliated islands,"
Liu reiterated the islands had been part of Chinese territory since ancient times and China's sovereignty over them was grounded in an indisputable historical and legal basis.
Earlier this year, Tokyo Governor Shintaro Ishihara proposed using public funds to buy the islands from private owners, prompting Beijing to denounce the plan as illegal and reassert its sovereignty.
Diplomatic ties between Beijing and Tokyo hit a low point in 2010 after Japan's arrest of a Chinese fishing boat captain.
In 2008, Beijing and Tokyo agreed in principle to jointly develop gas fields near the islands, but progress has been slow and Japan has accused China of drilling for gas in violation of the deal.
(Reporting By Xiaoyi Shao and David Stanway; Editing by Ron Popeski)