TAIPEI, Taiwan — President Tsai Ing-wen of Taiwan visited Houston over the weekend, her second brief stop in the United States in one week, a sign of efforts to deepen relations between Washington and Taipei despite vehement opposition from China.

Ms. Tsai stopped in Los Angeles last Monday, on her way to Paraguay and Belize, and then in Houston on Saturday on her way back home. During the earlier stop, she met with three California lawmakers, including one, Representative Brad Sherman, a Democrat, who called on the United States to formally invite her to Washington, which would break with decades of American practice.

The United States has not officially recognized Taiwan since 1979, when it shifted to recognizing China’s Communist government. China hopes to absorb the self-governed, democratic island, which it has never controlled, and has campaigned to erase any recognition by other countries or corporations of Taiwan’s sovereignty.

The visits to Houston and Los Angeles are considered “transit stops” rather than official visits, part of a longstanding restriction imposed by the United States to maintain better relations with China. But Beijing has objected even to such brief stopovers, and the most recent ones came after President Trump demonstrated willingness to provoke China’s anger.