Vandals damaged 40 percent of the buses used to bring about 18,000 students to public schools, leading officials to give children an unexpected day off from school Monday.

The city's schools were closed because 22 buses were broken into, with fire extinguishers sprayed inside, graffiti scribbled inside and out and other damage done, according to the office of David Snead, superintendent of schools.

The buses were vandalized sometime over the weekend, Snead said. Authorities would not comment further on the damage.

Waterbury, which has about 120,000 residents, is in central Connecticut.

In early October, Newark, Ohio schools were closed after vandals damaged the city's school bus fleet. The vandals discharged fire extinguishers, dumped trash in the buses and stuffed paper in the gas tanks.

Police questioned two fifth-grade boys who were seen on a surveillance camera at the bus lot.