BEIJING - Chinese publication authorities on Sunday urged the country's publishers not to promote teaching or learning materials in middle and primary schools.

The publishers are asked not to collude with school teachers who ask their students to buy learning materials in designated bookstores, according to a circular issued by the State General Administration of Press, Publication, Radio, Film and Television.

The circular asked publishers to strictly implement the country's price policy on teaching and learning materials for middle and primary school students.

The prices of such materials are asked to be made public on the publishers' official websites, according to the circular.

Publication authorities at all levels are also urged to carry out an overhaul in order to find any possible violations of the price policy, the circular added.