The war on teen smoking is heading to the toilet.

The oldest bastion of student smoking, boys' and girls' rest-rooms, is increasingly being targeted by school officials across the country.Students were locked out of the Manchester-by-the-Sea High School restrooms during class periods for three weeks last month. Students protested and health officials ordered the toilets reopened.

"What it was doing was punishing 400 students for the actions of about 10 students," said Bre Quinn, 18, president of the Student Council.

Similar battles are being waged in states such as Arkansas, where the Hartford high school principal began locking bathroom doors last month. Schools in Glen Burnie, Md., have had doorless bathroom stalls for six years to prevent smokers from hiding.

In Hawaii, the Department of Health told complaining students that it can't force schools to keep bathrooms open all the time. And in New Jersey, administrators in one district have won a partial victory in their fight to control the lavatories.

The debates are flaring up as states spend millions to get young people to kick the habit, while federal studies show more are smoking than ever.

Forty-three percent of the nation's high school students either smoke cigarettes or cigars or chew tobacco, according to a report by the Centers for Disease Control and Prevention.