Marie Royce, Assistant Secretary of State for Educational and Cultural Affairs, was one of the representatives for the U.S. government, with many officials accompanying President Donald Trump for his summit in Singapore with North Korea's leader Kim Jong-un.
Outgoing AIT Director Kin Moy described the American delegation as "perfect" for the occasion, saying the officials represented all of the cooperative areas between United States and Taiwan.
"We urge the United States to honor its pledges made to China on the Taiwan issue, correct its wrong practices to avoid damaging China-U.S. relations as well as peace and stability across the Taiwan Strait", said Geng.
Taiwan's relations with the United States have grown closer amid Washington's own struggles with Beijing.
In addition to Royce, U.S. Rep. Gregg Harper, AIT Chairman James Moriarty and others also attended event. Fewer than 20 countries consider Taiwan as an independent government.
Taiwan's President Tsai Ing-wen attended the opening ceremony, where she reaffirmed her government's commitment to its "vital relationship" with the U.S., Reuters reports. The policy dictates that the US formally recognize only one Chinese government - the Communist apparatus based in Beijing - and officially eschew relations with a Taiwanese government, which has proclaimed itself the "Republic of China".
The event underscores the deepening ties between the current USA administration and Taiwan, as China attempts to cut off Taiwan's diplomatic reach.
China's Foreign Ministry spokesman Geng Shuang on Tuesday said it had lodged stern representations with the U.S. about the new AIT building.
But the US still enjoys a "robust unofficial relationship" with the island nation of 23 million people, according to the State Department. This is despite the fact that no US or global law prohibits American officials, even the president, from traveling to Taiwan and meeting with Taiwanese counterparts.
A USA bill titled "Taiwan Travel Act" was passed unanimously by Congress and signed into law by Trump in March, which stipulates that the US administration should conduct more high-level official exchanges with Taiwan.
Washington's decision to "slightly upgrade relations" is mainly due to its disillusionment with China and the ascension of a more hawkish view toward China in the Trump administration, said Denny Roy, a fellow at the East-West Center think tank in Honolulu.
Cory Gardner, who recently visited Taiwan in late May, spoke first and took the opportunity to congratulate Taiwan on the opening of the new AIT complex in Neihu.
While Taiwan's relationship with the USA is essential to its security, it must also guard against provoking China, its biggest military threat but also the dominant market for the island's export-driven economy.