* No force can prevent 'reunification' of China, he says
* He calls China-US military relationship 'generally stable'
* Taiwan says China has endangered world peace
China's defence minister, Wei Fenghe, said on Monday that resolving the "Taiwan question" is his country's "greatest national interest", and that no force could prevent China's "reunification".
Separatist activities are doomed to failure, Wei said at the opening of the Xiangshan Forum in Beijing, which China styles as its answer to the annual Shangri-La Dialogue security forum in Singapore.
Tensions between China and Taiwan have ratcheted up ahead of the self-ruled island's presidential election in January. Taiwan is China's most sensitive territorial issue.
"China is the only major country in the world that is yet to be completely reunified," Wei said.
"Resolving the Taiwan question so as to realise China's full reunification is the irresistible trend of the times, China's greatest national interest, the righteous path to follow and the longing of all Chinese people."
Proudly democratic Taiwan has lambasted China for its authoritarian rule and for being a threat to regional peace, while China has heaped pressure on Taiwan, whittling away at its few remaining diplomatic allies.
Taiwan's Mainland Affairs Council called the forum in Beijing an "irony", saying China is "a factor of instability" that has led to rising tensions in the region.
"The Chinese Communist Party's intimidation of the use of force against Taiwan has threatened the world peace," the council said in a statement.
"The threat of force cannot shake the will to protect sovereignty and democracy of the 23 million people in Taiwan. The Beijing authority should give up the impractical wishful thinking of 'unification by force' at the soonest," the statement said.
China regards Taiwan as its sacred territory, to be brought under Beijing's rule, by force if needed, a message President Xi Jinping reiterated at the start of this year.
China translates the word "tong yi" as "reunification", but it can also be translated as "unification", a term in English preferred by supporters of Taiwan independence who point out that Beijing's Communist government has never ruled Taiwan and so it cannot be "reunified".
Defeated Nationalist forces fled to Taiwan in 1949 at the end of a civil war with the Communists. The People's Republic of China has never governed Taiwan, whose people have shown little interest in being ruled by autocratic Beijing.
China has also been angered by US support for Taiwan, including arms sales. Washington has no formal ties with Taipei, but is bound by law to provide the island with the means to defend itself.
"No one and no force can ever stop China's full reunification. We are committed to promoting the peaceful development of cross-Taiwan strait relations and the peaceful reunification of the country," Wei said.
"However we will never allow separatists for Taiwan independence to have their way, nor allow interference by any external forces. Advancing China's reunification is a just cause, while separatist activities are doomed to failure."
The US and China have clashed across multiple fronts in recent years, not only because of the bitter trade war but also because of efforts by Washington to check what it perceives as growing capabilities and aggressiveness of Beijing's armed forces in the Asia-Pacific region.
China asserts territorial claims in almost all of the energy-rich waters of the South China Sea, as do smaller neighbours Brunei, Malaysia, the Philippines, Taiwan and Vietnam. But those countries are unable to keep pace with China's military spending, which at nearly $170 billion this year is second only to that of the US
Washington has spoken out against what it calls China's "coercion" of Southeast Asian neighbours, further adding to tensions.
Wei on Monday reiterated that Beijing is a "peace-loving nation" that would never strike first and does not pose a threat to the rest of the world.
"The China-US military relationship is generally stable but we are confronted with many difficulties and challenges," he said. "Cooperation between the two militaries on strategic communication, mutual trust and risk control should be further strengthened."
The US has also angered China by repeatedly conducting what it calls "freedom of navigation" operations by ships close to islands China occupies in the South China Sea.
"The South China Sea islands and Diaoyu islands are inalienable parts of China's territory. We will not allow even an inch of territory that our ancestors have left to us to be taken away," Wei said.