The US State Department has said it is deeply concerned over China’s “worsening crackdown” on minority Muslims in China’s northwestern territory of Xinjiang as the Trump administration reportedly considers sanctions against senior Chinese officials and companies linked to allegations of human rights abuses.

China’s “strike hard” campaign in the name of countering terrorism has seen an estimated one million people, mostly ethnic Uighurs, Kazakhs and other minority groups, detained in a network of secretive internment camps, according to reports.

“We’re deeply troubled by the worsening crackdown, not just on Uighurs (but also) Kazakhs, other Muslims in that region of China,” state department spokeswoman Heather Nauert told a news briefing, renewing concerns expressed in recent months by top administration officials.

At the end of August, a group of US lawmakers asked US secretary of state Mike Pompeo and treasury secretary Steven Mnuchin to place sanctions on seven Chinese officials, including Chen Quanguo, Communist party chief in Xinjiang, who has overseen the crackdown. A US official told Reuters the idea of sanctions was still in the discussion stage.

“There are credible reports out there that many, many thousands have been detained in detention centers since April 2017, and the numbers are fairly significant from what we can tell so far,” Nauert said.

The government is also considering sanctions on Chinese companies involved in building detention camps and surveillance systems used to track and monitor Uighurs, according Reuters, citing congressional sources.

Nauert declined to discuss details of any US government action. “We’re not going to preview any sanctions that may or may not happen,” Nauert said.

Any sanctions decision would be a rare move on human rights grounds by the Trump administration against China. The US is is currently engaged in a trade war with China, while also seeking its help to resolve a standoff over North Korea’s nuclear weapons.

The sanctions could be imposed under the Global Magnitsky Act which allows the US government to freeze the US assets of human rights violators, bar them from traveling to the US, and prohibit Americans from doing business with them.

Police patrolling the Old Town in Kashgar, Xinjiang Photograph: Tom Phillips/The Guardian

The Washington-based Uyghur Human Rights Project tweeted a photo of activist Dolkun Isa, president of World Uyghur Congress, at the White House on Monday along with the comment: “A meeting with White House officials today provided much-needed encouragement for Uyghur human-rights advocates.”

Isa said he had the impression from the Americans that “they are seriously considering” imposing sanctions on senior Chinese officials, including Chen, the Party chief in the far western region.

Ministry of foreign affairs spokesman Geng Shuang on Tuesday responded to UN human rights commissioner Michelle Bachelet’s appeal to China to allow monitors into Xinjiang. Geng said the commissioner should “respect China’s sovereignty ... and not listen to and believe one-sided information.”

The government crackdown has turned Xinjiang into what critics call a police state where minorities are routinely subjected to security checks, interrogation, and surveillance that the majority Han Chinese do not experience.

According to a Human Rights Watch report released this week, based on interviews with 58 former residents of Xinjiang, authorities use high-tech mass surveillance such as big data analysis, artificial intelligence, and the collection of DNA and voice biometrics to “identify, profile, and track everyone in Xinjiang.” Some families have QR codes placed on their homes so police can quickly access their personal information.

“For the first time, we are able to demonstrate that the Chinese government’s use of big data and predictive policing not only blatantly violates privacy rights, but also enables officials to arbitrarily detain people,” said Maya Wang, senior China researcher at Human Rights Watch.

Beijing has said Xinjiang faces a serious threat from Islamist militants and separatists who plot attacks and stir up tension between the mostly Muslim Uighur minority who call the region home and members of the ethnic Han Chinese majority.

It has denied the use of political indoctrination in camps and said that China uses “vocational and training” centres to offer skills and legal training to residents, as well as “education to transform the thoughts” of already detained “religious extremists”.

Reuters contributed to this report