BOSTON -- Rats forced a Boston-area elementary school to shut down Thursday for the second time in two weeks, Boston TV station WCVB reported.

The rodents were first detected at Waybright Elementary in Saugus in December.

Exterminators were brought in, but on Wednesday a rat was found in a vent inside a kindergarten classroom, forcing the school to close Thursday and hold classes at the local high school.

School officials were told the problem was taken care of.

"Got that assurance and they returned on Monday. We thought we were getting the better of the situation," Saugus schools Superintendent Richard Langlois said.

Parents met with school administrators Wednesday night, and were furious.

"It really is scary to think about sending my son back there," parent Lorie Cassier said. " The school's closed for tomorrow. But what are they going to do the day after?"

"They say it's contained to the basement, but for them to see them in the academic areas, the classrooms, it's not a contained problem," parent Lou Moran said.

"I think it's absolutely disgusting and it's been like this for weeks," parent Wendy Mills said.

The school will undergo another inspection. Parents want the school closed through the February vacation break so that exterminators can focus on getting the rats out of there for good.

Langlois said he can't offer any guarantees on the problem.

"There is no assurance," he said. "It's one of those things. You do the best you can."

"My kids are, every morning, telling me they don't want to get bit by a rat. I think it's sad that I have to send them there," Mills said.