Suspected Taliban militants have been blamed for orchestrating a poisonous gas attack on at least three girls-only-schools in Afghanistan that saw over 300 children being admitted to hospitals.

The police are investigating at least three incidents of "mysterious" gas attacks that left the affected children unconscious.

More than 300 schoolgirls in the age-group of nine to 18 had fallen ill in their schools after breathing the toxic gas, CNN reported. According to reports, 115 girls were admitted to hospitals on Thursday, 50 on Wednesday and 126 on Monday after they inhaled some gas and displayed signs of poisoning.

The Daily Mail reported that Taliban militants, who are opposed to girls' education, are suspected to be behind the "deliberate act".

A Herat provincial council member, Sakina Hussaini told an Afghan news agency that the "insurgents" (referring to the Taliban) could not fight the security forces and have now resorted to poisoning innocent children. Several schoolteachers and the headmistress of a school were among those poisoned, Kabul-based Pajhwok reported. 

Herat, which is the third largest city of Afghanistan, has witnessed several attacks against schoolgirls as many ultra conservative Afghans believe that girls should not be sent to school.

In July, assailants had thrown acid on the faces of three teenaged girls on their way to school in Herat province. The girls aged 16 and 18 were students of a well-known school.

The attackers, while pouring the acid, had told the girls that it was a punishment for "going to school".