Last week, four women believed to be members of the Islamic militant group Boko Haram carried out attacks in Kano, a city in northern Nigeria. Men belonging to the group have taken to wearing the hijab, too, according to reports.

On July 27, a female suicide bomber detonated a bomb outside a Roman Catholic church in Kano, killing four people and injuring 70. Around the same time, security agencies arrested two girls aged 10 and 18 with explosive belts under their hijabs.

“We have this worrying situation where the bombers are turning out to be girls dressed in the hijab,” Roman Catholic Bishop John Niyiring of Kano said.

Banning the hijab is crucial to curbing the trend, said Emmanuel Akubor, a historian at Obafemi Awolowo University in Ile-Ife in western Nigeria.

“The best thing for now is to place a temporary ban on hijab, not for religious, but security reasons,” he told News Agency of Nigeria.

But Niyiring said he thinks such a ban would be resisted.

Muslims are opposed to the ban, saying it will not curb insecurity, while the Nigeria Bar Association says women have a right to the covering, meant to convey a sense of modesty.

At the same time, attacks by female suicide bombers are fueling speculation that Boko Haram may have turned the 200 schoolgirls it abducted in April into deadly killers. That speculation is so far unfounded.