The Taiwan Strait's median line previously served as an unofficial barrier between Taiwan and China, but Chinese fighter jets, drones and now balloons regularly fly over it.
Taiwan voted for the ruling Democratic Progressive Party's (DPP) Lai Ching-te as its next president on Saturday, a man Beijing has repeatedly blasted as a dangerous separatist and bringer of war.
Does the US really have the conventional military means to deter and counter a comprehensive invasion of China against Taiwan?
In a show of support for the government, Biden plans to dispatch an unofficial delegation to the self-governed island.
Although Taiwan may be a small country with an electorate of around 19 million, the upcoming election is particularly significant and considered the most important one in Asia.
Taiwan's president says China must respect the outcome of its election, having repeatedly warned China is trying to interfere in the election.
China has been stepping up its missions near Taiwan as the January 13 presidential and parliamentary elections on the island approach.