Primary and middle school students nationwide can use only textbooks approved by the Ministry of Education, and no adaptations or changes can be made, the ministry said on Wednesday.

Some textbook publishers have made changes to the national standard textbooks, while some schools have been using their own textbooks or textbooks from other countries, the ministry's Institute for Curriculum and Textbooks said in a statement.

Local education authorities should conduct a thorough inspection of all primary and middle schools within their jurisdictions by Oct 15, the statement said.

Publishers have until Oct 10 to examine their textbooks, it said, adding that they should submit a report about any changes made and the corrective measures they plan to take.

The institute was established in July 2017 by the State Council to manage affairs related to school textbooks.

The institute is also charged with guiding the overall work involving textbooks - organizing and coordinating different regions and departments, reviewing the nation's curricula and setting standards.