The Biden administration is vowing to continue sailing warships through the Taiwan Strait and to conduct air operations in the region in response to Chinese military drills that U.S. officials say are evolving into a long-term strategy of heightened military pressure on the island.

Administration officials said they did not want to escalate the tense confrontation, which China maintains was provoked by last week’s visit to the island by Speaker Nancy Pelosi. But in interviews and public statements, American and Taiwanese officials made clear they now believe China used Ms. Pelosi’s visit as a pretext to step up its operations to intimidate Taiwan for months or years to come, and perhaps speed the timetable of its plans to establish control over the island’s 23 million people, much as it did in Hong Kong.

Within a few weeks, officials said, the U.S. Navy is planning to run ships through the Taiwan Strait, ignoring China’s recent claim that it controls the entire waterway. Officials said they would not send the Ronald Reagan, the Japan-based aircraft carrier, because it would be too provocative.