The US is considering sending a warship through the Taiwan Strait, in a move that could provoke a sharp reaction from Beijing at a time when Sino-US ties are under pressure from trade disputes and the North Korean nuclear crisis.
A US warship passage, should it happen, could be seen in Taiwan as a fresh sign of support by President Donald Trump after Chinese military drills around the self-ruled island.
China claims Taiwan as part of its territory.
The last time a US aircraft carrier transited the Taiwan Strait was in 2007, during the administration of George W Bush, and some US military officials believe a carrier transit is overdue.
Mr Trump, who broke protocol as president-elect by taking a phone call from Taiwan’s president in 2016, has toned down his rhetoric about Taiwan in recent months as he seeks China’s aid in the nuclear stand-off with North Korea.
The US and China are also trying to find their way out of a major trade dispute that has seen the world’s two economic heavyweights threaten tit-for-tat tariffs on goods worth up to $US150 billion ($196 billion) each.
China has alarmed Taiwan by ramping up military exercises this year, including flying bombers and other military aircraft around the island and sending its carrier through the narrow Taiwan Strait separating it from Taiwan.
Since taking office, Trump has approved a $US1.4 billion arms sale to Taiwan and angered Beijing by signing legislation encouraging visits by senior US officials to Taiwan.
Mr Trump also named John Bolton, known as a strong Taiwan supporter, as his national security adviser.
Military experts say the balance of power between Taiwan and China has shifted decisively in China’s favour in recent years, and China could easily overwhelm the island unless US forces came quickly to Taiwan’s aid.
The US is bound by law to provide Taiwan with the means to defend itself, but it is unclear whether Washington would want to be dragged into war with China over the island.