Azerbaijan will punish parents who defy a ban on girls wearing the hijab in schools in the mainly Muslim but officially secular state, the education ministry said on Wednesday. "We will take action against those parents who don't let their children attend classes because of the ban on wearing the hijab," education ministry spokeswoman Zamina Aligyzy said. The headscarf is prohibited under rules that define what uniforms pupils must wear in ex-Soviet Azerbaijan. The ban has led to a series of demonstrations by pious believers, but Aligyzy said that parents who kept their children from school were breaking the law. "We are getting calls from girls who inform us anonymously that they do want to go to school but their parents don't let them do so, saying that they must wear the hijab," she said. The US State Department criticised the hijab ban in a report on religious freedoms worldwide that was published on Tuesday, describing it as a "negative" development. The State Department also criticised the Azerbaijani government for the continued closure of several mosques and for increasing fines for violating laws regulating religious activities. Azerbaijan is an important energy supplier to the West and an ally in the Nato-led campaign in Afghanistan.