Story highlights At least 140 Afghan girls and female teachers were admitted to a local hospital

Their drinking water had been poisoned, health officials say

No deaths have been reported

In 2010, more than 100 schoolgirls and teachers were sickened in similar poisonings

At least 140 Afghan schoolgirls and female teachers were admitted to a local hospital Tuesday after drinking poisoned water, said local health officials, who blamed the act on extremists opposed to women's education.

The victims range in age from 14 to 30 and were taken to a hospital in Afghanistan's northeastern Takhar province after their school's water tank was contaminated, according to provincial health department director Dr. Hafizullah Safi.

No deaths were reported, but more than half the victims partially lost consciousness, while others suffered dizziness and vomiting.

"Looking at the health condition of these girls, I can definitely say that their water was contaminated by some sort of poison," Safi said. "But we don't know yet what was the water exactly contaminated with."

Local officials said they are investigating the incident at the Rostaq district school and are searching for the perpetrators.

"It is the work of those who are against girls' education and peace and stability in Afghanistan," district administrator Malem Hussain said.

In 2010, more than 100 schoolgirls and teachers were sickened in a series of similar poisonings.

During the Taliban's rule from 1996 to 2001, many Afghan girls were not allowed to attend school, though the schools began reopening after the regime was toppled by the U.S.-led invasion.

Observers say, however, that abuse of women remains common in the post-Taliban era and is often accepted in conservative and traditional families, where women are barred from education and commonly subjected to domestic violence.

In January 2011, Afghan Education Minister Dr. Farooq Wardak told the Education World Forum in London that the Taliban had abandoned their opposition to girls' education. But the group never offered a statement confirming or denying that claim.

Female educational facilities, students and teachers, meanwhile, have come under vicious attack as the insurgency has spread outside Taliban strongholds in the southern provinces of Kandahar and Helmand.

The country maintains one of the world's youngest populations, though officials say literacy rates among both children and adults remain low.