Changing position on China's claims over the South China Sea would shame its ancestors, while not facing up to infringements of Chinese sovereignty there would shame its children, Foreign Minister Wang Yi said on Saturday.
China has become increasingly assertive in the South China Sea, building artificial islands in areas over which the Philippines and other countries have rival claims, sparking alarm regionally and in Washington.
"One thousand years ago China was a large sea-faring nation. So of course China was the first country to discover, use and administer the Nansha Islands," Wang said, using the Chinese term for the Spratly Islands, which together with the Paracel Islands form the bulk of China's claims.
"China's demands of sovereignty over the Nansha Islands have not expanded and neither will they shrink. Otherwise we would not be able to face our forefathers and ancestors," the normally taciturn Wang said in unusually strong comments.
China claims most of the potentially energy-rich South China Sea, through which US$5 trillion in ship-borne trade passes every year. The Philippines, Vietnam, Malaysia, Brunei, and Taiwan also have overlapping claims.
Speaking to academics and former officials, Wang said China could not face its children and grandchildren if "the gradual and incremental invasion of China's sovereignty and encroachment on China's interests" was allowed to continue.
He said US ships took Chinese troops to reclaim the Spratlys after they were occupied by Japan during World War Two. Other countries only started occupying what he said was Chinese territory from the 1960s after oil was discovered.
"China is in reality the biggest victim," Wang said.
On Friday, the US State Department's number two diplomat compared China's behavior in pursuit of territory in the South China Sea to that of Russia in eastern Ukraine.
Wang did not address those comments, but defended China's land reclamation and building work in the South China Sea as necessary to improve living conditions, pointing out that other countries had been building there since the 1970s.
"It is only recently that China has started necessary development," he said.