Taiwan's leader, officials and media have strongly protested against Japan's move to "purchase" parts of the Diaoyu Islands.

Japan's Chief Cabinet Secretary Osamu Fujimura announced Monday afternoon that the Japanese central government had reached an agreement with the proclaimed "owners" to buy three of the five uninhabited islands.

Japanese media reported on Tuesday that the Japanese government had signed the contract over the "purchase."

Taiwan leader Ma Ying-jeou said on Monday that he was closely monitoring the situation and Taiwan authorities would take appropriate action to deal with it.

He added that the island would not back down if the Japanese government moved ahead to sign the "purchase" agreement.

Steve Hsia, a senior official of Taiwan authorities, warned Japan against taking the unilateral move.

He said that Taiwan would not accept Japan's claim of sovereignty over the Diaoyu Islands and Japan's move to "purchase" them was "invalid."

Lee Tung-hao, a ranking member of the People First Party, said he would propose a draft at the local legislative body to require all related bodies of the Taiwanese authorities to work together to defend the sovereignty over the Diaoyu Islands.

Wu Yu-sheng, a senior member of the ruling Kuomintang Party, said a serious protest should be lodged with the Japanese government.

Taiwan media outlets have reported extensively on the latest developments.

The United Daily News said the latest move by the mainland to announce the base points and baselines of the territorial waters of Diaoyu Islands is a "strong counter-strike" against Japan.

The comments clearly state that the areas around the Diaoyu Islands are Chinese territorial waters and it serves as another move to assert sovereignty, according to them.