The US is committed to defending Taiwan if it comes under attack from China, according to US President Joe Biden.
He was asked twice during a CNN town hall on Thursday if the US would protect Taiwan when attacked and answered, "Yes, we have a commitment to do that," the broadcaster reported.
Biden said while the US is not seeking conflict with China, Beijing must understand: "We are not going to step back and change any of our views."
Taiwan's presidential spokesman Xavier Chang welcomed the comments on Friday, saying the US had demonstrated "rock solid" support to Taiwan since Biden took office in January.
Taiwan is a self-governing democratic island off the south-east coast of China, but Beijing claims it as a province and has threatened to take it by force if it makes any moves towards formal independence.
The US has committed to supporting Taiwan's defence capabilities, but so far that has meant mainly arms deliveries. The question of military assistance in the event of an attack has mostly been left open deliberately.
Declarations of military assistance from the US have generally been reserved for close allies South Korea and Japan, where US forces have a significant military presence.
Tensions around Taiwan have recently increased significantly. A record number of Chinese military aircraft recently entered Taiwan's Air Defence Identification Zone. The zone was established unilaterally rather than being internationally defined.