Schools in China's mainly Muslim Xinjiang region, where a series of attacks has left hundreds dead in recent months, said they would actively discourage religious practice at home, state-run media reported Wednesday.

Principals at more than 2,000 kindergartens, primary schools and secondary schools in Kashgar, near China's border with Pakistan, signed a pledge to "defend schools against the infiltration of religion", according to a report by the Global Times, which is close to the Communist Party.

Party members, teachers and underage students should not practise religion either at school or at home, it quoted a Kashgar education official as saying.

Xinjiang is home to more than 10 million Muslims, mostly members of the Uighur minority, some of whom chafe under Beijing's rule. Children younger than 18 are banned from entering mosques throughout the region.

Beijing has blamed a series of recent violent attacks on separatists from Xinjiang motivated by religious extremism, and linked them to overseas groups.

Rights groups accuse China's government of cultural and religious repression which they say fuels unrest.

Kashgar's education bureau has sought to fight extremism by regulating student dress, said the official quoted in the Global Times report, who expressed concern over students displaying no religious affiliation at school but then going home to study it under their parents' guidance.

China's constitution guarantees freedom of religion and a policy document released by the ruling Communist party on Wednesday said cadres must pledge allegiance to the constitution before taking office.

A US State Department report on religious freedom in China noted "societal discrimination based on religious affiliation, belief, or practice".

"Authorities often failed to distinguish between peaceful religious practice and criminal or terrorist activities," the report said.