Afghan officials say 160 students from a girl's school suffered symptoms of poisoning and had to be rushed to a hospital Tuesday, in the second such incident in a week.

Authorities in the northern province of Takhar have launched an investigation, saying blood samples from the affected girls and four teachers have been sent to a laboratory in Kabul for testing. They suspect classrooms at the Aahan Dara Girls school in Taloqan, the provincial capital, may have been sprayed with poison.

Some victims said they smelled something unusual after entering their classrooms, then became ill. After vomiting many lost consciousness.

No one claimed responsibility for Tuesday's incident. But officials often blame the Taliban for attacks on girls' schools aimed at shutting them down.

Under Taliban rule in the 1990s, women were banned from working or going to school.

Last week, 120 students suffered similar symptoms and had to leave a school in Takhar.

After that incident, the Taliban issued a statement denying it was involved.