The Chinese government has ordered the suspension of certain Advanced Placement (AP) exams in an effort to crack down on educational material that the Communist Party deems “unfriendly.” The censored material includes AP tests on United States history.

Chinese students seeking college credit for colleges in the United States will no longer be able to take the banned AP exams, which Beijing had ordered for suspension on Thursday, according to a report by Reuters. The blocked educational material is expected to be completely suspended by 2020.

“This is a bit sudden, we don’t know the reason,” said a Nanjing-based center, SAT Test Web, in a posting on social media site WeChat. “If you apply for any of these four subjects, it means you need to go to other exams outside the mainland.”

AP tests are provided by the American non-profit organization, College Board. A spokesman for the New York-based College Board told Reuters that it had never denied students access to AP exams before.

Last September, China’s education ministry launched an inspection of school textbooks in an effort to root out any material that would displease the Communist regime. The Chinese government is reportedly seeking to place a stronger focus on Communist ideology and history with regards to “educational material.”

The report also noted that negative viewpoints on topics such as the Tiananmen Square crackdown, the Sino-Japanese War, and the South China Sea are already strictly censored in China, adding that the country’s cyber laws make it a criminal offense to share unapproved content on the Internet.

This month, China’s education ministry warned students that studying in the United States could be risky, pointing to visa restrictions.

The suspension arrives after President Donald Trump’s trade war with the Communist regime, and China’s government-controlled media condemning U.S. policies, referring to the Trump administration’s trade policy as “the most barbarian method ever in the history of modern international economic and trade relations.”

In addition to U.S. history, China will also censor AP tests on European history, world history, and human geography. Advanced courses and exams in science, mathematics, and other subjects will reportedly be unaffected.

You can follow Alana Mastrangelo on Twitter at @ARmastrangelo, on Parler at @alana, and on Instagram.