BEIJING, Sept. 26 (Xinhua) -- A spokesman on Wednesday reiterated China's opposition to foreign interference on Taiwan affairs, saying the fate of the island should be decided by the 1.3 billion Chinese people living across the Taiwan Strait.

An Fengshan, spokesman for the Taiwan Affairs Office of the State Council, made the remarks when asked to comment on U.S. President Donald Trump's Taiwan policy, revealed partially in a recent best-selling book by Bob Woodward and the U.S. stance on Taiwan's unification with the mainland.

Describing Taiwan's unification with the mainland as an unstoppable historic trend, An said that "anyone trying to fight the trend by borrowing influence from foreign powers will ultimately harm the immediate interests of the Taiwan people."

The status of Taiwan is an internal affair for China and "we firmly oppose to any foreign interference," said An, adding "while we will strive for the peaceful unification with utmost sincerity, we stand firm in safeguarding national sovereignty and territorial integrity."

The spokesman also weighed in on a U.S. State Department spokesperson's criticism on El Salvador's decision to establish diplomatic relations with China, saying the United States is adopting double standards and has violated its one-China policy.