More than 300 schoolgirls were hospitalized in Afghanistan this week after being exposed to mysterious toxic fumes in what is suspected to be a deliberate attack by Taliban militants, according to the Daily Mail.

Aseeluddin Jami, the deputy governor of Herat province, said he believes the incidents were deliberately caused, though he did not provide his opinion on who or what group may have been responsible.

Today, 115 girls from a school in Herat city were hospitalized. Another 140 girls from a different school in the city were sent to the hospital Monday under similar circumstances, with 68 more girls falling ill from the same school Wednesday. The schoolgirls affected by the poison gas attack were aged 9 to 18, reported CNN.

Authorities have already promised to track down those who were responsible.

Attacks against schoolgirls in Afghanistan have been happening with alarming frequency lately, mainly by members of the country's ultra-conservative society who strongly oppose education for girls.

In July, men on motorbikes attacked three girls who were on their way to school, throwing acid on their faces. Two of the girls were critically injured.

From 1996-2001, when the country was under Taliban rule, girls and women were forbidden to study in school. They were also not allowed to pursue a career in the workplace.