The State Department said Friday it will make it easier for US officials to meet Taiwanese representatives, defying pressure from China amid high tensions.
The United States will still consider only Beijing as China's legitimate government, consistent with its switch of recognition in 1979, but will do away with some of the convoluted rules that restricted contacts with Taiwan.
"The guidance underscores Taiwan is a vibrant democracy and an important security and economic partner that is also a force for good in the international community," State Department spokesman Ned Price said.
"These new guidelines liberalize guidance on contacts with Taiwan, consistent with our unofficial relations," he said.
The move by President Joe Biden's administration formalizes increasingly vocal US support for Taiwan, a self-government democracy, and comes in response to an act of Congress that required a review.
Former secretary of state Mike Pompeo, a staunch critic of Beijing, in his last days in office said he was getting rid of previous guidelines on dealing with Taiwan -- a step praised by many supporters of Taipei but which also caused confusion as he did not state what would replace them.
In a sign of the new approach, the Biden administration last month sent the US ambassador to Palau on a visit to Taiwan to accompany the island nation's president.
China considers Taiwan, where the mainland's defeated nationalists fled in 1949 after losing the civil war, to be a territory awaiting reunification, by force if necessary.
Taiwan has reported growing air incursions by Beijing. Under US law, Washington is required to provide Taiwan with weapons for its self-defense.