(CNN) -- Nearly 400 boys at a school in Afghanistan's Khost province fell ill after drinking water from a well that may have been poisoned, a health official said Tuesday.
Eighty of the 389 boys treated for illness Tuesday morning remained hospitalized, two of them in critical condition, said Amir Padshah Mangal, director of the provincial health department.
"I don't exactly know who has done it yet, but it is definitely an inhumane action against the children of this country and against education in this country," Mangal said.
A water sample has been sent to Kabul for testing, he said.
The incident happened at a school in the Ismail Khan Mandokhil district of southeastern Khost province. The area is 20 kilometers (12 miles) from the provincial capital, Khost.
Similiar poisonings have been reported since at least 2010, when more than 100 female students and teachers were sickened in a series of similar poisonings.
Last month, more than 170 women and girls were hospitalized after drinking apparently poisoned well water at a school in the northeastern province of Takhar.