WASHINGTON — The State Department approved on Thursday selling more than $1 billion in arms to Taiwan in yet another sign that the Trump administration is embracing a far more confrontational approach with China.

Heather Nauert, a State Department spokeswoman, underscored that the military sales have no effect on the United States’ “One China” policy, which President Trump suggested in December may be under review. Mr. Trump later affirmed to Chinese President Xi Jinping that he would honor the decades-old policy, under which the United States recognized a single Chinese government in Beijing and severed its diplomatic ties with Taiwan.

The arms sale is the most tangible sign yet that Mr. Trump’s honeymoon with Mr. Xi is over. The American president had set aside tough moves on trade and regional issues in an informal quid pro quo for Mr. Xi’s commitment to further pressure North Korea.