The voting is underway in Taiwan to elect the new president amid Chinese threat.
China has said that choosing the wrong leader could set the stage for war on the self-ruled island.
It has slammed frontrunner Lai Ching-te, the current vice president, as a dangerous "separatist" in the days leading up to the poll, AFP reported.
Also, on the eve of the vote, its defence ministry vowed to "crush" any move towards Taiwanese independence, the report said.
China claims Taiwan as its own territory and says it will not rule out using force to bring about "unification", even if conflict does not appear imminent.
The voting as per the report began at 8:00 am (0000 GMT) at nearly 18,000 polling stations across the island, with almost 20 million people eligible to cast ballots.
Lai Ching-te vs Hou Yu-ih:
Results are expected Saturday evening, with the outcome watched closely from China to US.
During a raucous campaign, Lai, of the Democratic Progressive Party (DPP), pitched himself as the defender of Taiwan's democratic way of life.
His main opponent, Hou Yu-ih, of the opposition Kuomintang (KMT), favours warmer ties with China and accuses the DPP of antagonising Beijing with its stance that Taiwan is "already independent".
Strategically important Taiwan:
Taiwan is located on a key maritime gateway linking the South China Sea to the Pacific Ocean.
The country is home to a powerhouse semiconductor industry producing precious microchips -- the lifeblood of the global economy powering everything from smartphones to cars and missiles.
China’s hegemony on Taiwan:
China has stepped up military pressure on Taiwan in recent years, periodically stoking worries about a potential invasion.
Chinese President Xi Jinping in a recent New Year's address said the "unification" of Taiwan with China was "inevitable".
