After Mr. Trump and President Xi Jinping of China talked over a steak dinner in December at a Group of 20 meeting in Argentina, the administration decided to shelve the proposed sanctions, according to the American officials. The two leaders had set a deadline of March 1 to reach a broad trade agreement, and American officials decided the sanctions could wait until after that deadline. But trade negotiators failed to reach a deal by that date, and talks are still continuing.

China has cracked down on ethnic minorities like the Uighurs, a Turkic-speaking group of mostly Sunni Muslims, who form the largest ethnic group in Xinjiang. For decades, many Uighurs have resented Communist Party rule, saying Chinese officials suppress their culture and religion and practice widespread discrimination.

Officials in Beijing say they fear terrorist ideas have taken root among the Uighurs and point to outbursts of violence in recent years, particularly a deadly riot in the capital of Xinjiang in 2009. A vast internment program began soon after, largely under the orders of Chen Quanguo, who became party chief of Xinjiang in August 2016, after a stint in the Tibet Autonomous Region.

Of the majority-Muslim nations, only Turkey has strongly denounced the recent mass detentions and surveillance in Xinjiang, though Ankara maintains strong economic ties to Beijing.

“Beijing hasn’t significantly changed its policies in Xinjiang,” said Sophie Richardson, China director for Human Rights Watch. “So it’s still appropriate the United States go ahead with the sanctions.”

As a last-ditch effort, activists are now pushing American officials to insert the humanitarian crisis in Xinjiang into the trade talks, which may wrap up next week in Washington, or to impose sanctions to pressure China to end persecution in the region.

On Friday, a group of about a dozen demonstrators, many of whom are Uighurs living in the United States, gathered in Washington outside of a conference focused on sanctions policy to pressure Treasury Department officials to take action against Chinese officials involved in the Xinjiang abuses under the Global Magnitsky Act.