SAN FRANCISCO (Reuters) - Ten middle school students in San Francisco were rushed to hospitals on Tuesday after ingesting an unidentified substance, possibly an illicit drug, but all were expected to recover, officials said.

Emergency personnel treated the students at James Lick Middle School in the Noe Valley neighborhood, before sending them by ambulance to hospitals in the area, fire department spokesman Lieutenant Jonathan Baxter told Reuters in an email.

None of the students’ illnesses was life-threatening, he said, offering no further details and referring queries to school officials.

“The specific substance is still being determined,” the San Francisco Unified School District said in a statement.

Ethan Baker, a representative for the city Emergency Management Department, said the substance in question was possibly an illicit drug.

The mishap unfolded at about 1:20 p.m. local time when a student came to the school office “reporting an illness after having ingested some kind of substance,” the school district statement said.

Additional students who had consumed the substance soon came forward to complain they, too, were feeling unwell, “and medical providers at the scene were immediately notified,” the statement said, adding that 10 youngsters in all were treated.

The school alerted parents and advised them to seek medical help if their children experienced such symptoms as nausea, vomiting, unusual behavior “or an altered level of consciousness,” the school district said.

Students throughout the school were also notified of the incident and assured “they will not be in trouble if they come forward to seek medical help.”

According to the James Lick website, the school serves about 650 students in grades six through eight.