Taiwanese officials say Taiwan's foreign affairs chief has met US National Security Advisor John Bolton to discuss security.
It is quite rare for high-ranking officials of the US and Taiwan to meet because the two have no formal diplomatic ties.
Taiwan's foreign ministry announced on Saturday that foreign affairs chief David Lee visited the United States between May 13 and 21.
The officials say Lee met Bolton in Washington. But the date and place of the meeting was not released.
Last year, the US Congress passed an act to encourage mutual visits between US and Taiwanese officials at all levels.
Observers say China is expected to lodge a protest with the US for its contact with Taiwan.