(Adds comment from Taiwan government)
By Yew Lun Tian
BEIJING, Oct 25 (Reuters) - President Xi Jinping vowed on Monday that China would always uphold world peace and international rules, amid concerns expressed by the United States and other countries over its increasing assertiveness globally.
The comments come after Taiwan said this month that military tension with China was at its worst in more than 40 years, amid mounting worries that the giant neighbour might try to take back by military force the self-ruled island it claims as its own.
In a speech marking the 50th anniversary of China's return to the United Nations, Xi said it would always be the "builder of world peace" and a "protector of international order", state news agency Xinhua reported.
"China resolutely opposes all forms of hegemony and power politics, unilateralism and protectionism," Xi said, calling for greater global cooperation on issues such as regional conflicts, terrorism, climate change, cybersecurity and biosecurity.
Xi urged all countries to promote the values of peace, development, justice, democracy, freedom, making use of a phrase the "common values of all mankind" that he coined and first mentioned in a July speech for the 100th anniversary of the ruling Chinese Communist Party.
In 1971, the United Nations voted to recognise the People's Republic of China as the sole representative of China, expelling Taiwan, which had held the U.N. seat in the name of the Republic of China, its official title.
Taiwan's foreign ministry reiterated a call for the United Nations to allow its "meaningful participation", adding that the island had never been part of the People's Republic and its government had no right to represent the island's people.
The ministry called on the United Nations "not to repeatedly succumb to the political pressure of the Chinese government" and exclude Taiwan, it added.
Apart from tension with Taiwan, China has been more assertive in staking its claims to disputed territory on its Himalayan border with India, and to tracts of the South China Sea disputed with some Southeast Asian nations, and over some islands in the East China Sea disputed with Japan.
Xi said reforms on global governance are needed, and that international rules should be decided by all 193 members of the United Nations, instead of by "certain countries or country groupings", making a veiled criticism of the United States for exerting a dominant influence over international institutions.
He also said all countries should always abide by international rules, and not only when the rules suit them. (Reporting by Yew Lun Tian; Additional reporting by Ben Blanchard in Taipei; Editing by Clarence Fernandez & Simon Cameron_Moore)