Police in Azerbaijan on Friday broke up a protest by Islamic activists against a law that effectively bans the wearing of the hijab in schools in the mainly Muslim ex-Soviet state.

Several hundred demonstrators rallied outside the education ministry in the capital Baku, chanting "God is great!" and demanding the resignation of Education Minister Misir Mardanov.

Some demonstrators started to throw stones at police and more than a dozen were detained.

After several other protests in recent months, Mardanov defended the law regulating what pupils must wear in schools that effectively prohibits the Muslim headscarf, insisting that it is not anti-Islamic.

Energy-rich Azerbaijan is a mainly Shiite Muslim country, but after decades of Soviet rule it emerged as one of the most secular states in the Muslim world.

The authorities have imposed restrictions on religious worship and arrested radicals in attempts to prevent the spread of extremism, although critics have accused them of persecuting devout Muslims.