India, Oct. 15 -- A school dress-code dispute has opened an unusual rift between two close allies: Azerbaijan and Turkey.

The controversy centres on a question that has become politically sensitive across parts of the Muslim world - whether wearing an Islamic headscarf should be permitted in public schools that operate under a secular system.

Azerbaijan, where around 96 percent of the population identifies as Muslim, has introduced rules requiring pupils and teachers in state schools to comply with dress codes aligned with the country's secular principles.

The regulations do not explicitly name the hijab, but reports that schools have turned away girls wearing headscarves have triggered protests and a debate over religious freedom and ...