Defense spending in Taiwan has not kept pace with the threat posed by China and should be increased, a senior U.S. defense official said on Tuesday, days after President-elect Donald Trump touched off a storm by questioning American policy over the island.

Deputy Assistant Secretary of Defense Abraham Denmark said the Obama administration's "one China" policy remains unchanged but he could not predict Trump's intentions after he takes office on Jan. 20.

Trump set off a diplomatic firestorm over the weekend when he questioned why the United States should be bound by the long-standing policy under which Washington recognizes Beijing rather than Taiwan, which China considers a renegade province.