TULSA, Oklahoma - In the wake of the massacre at Sandy Hook Elementary, in Newtown, Connecticut, local schools have been on high alert.

Sites in the Tulsa Public Schools district have gone on lockdown several times, and the police chief says they are being abundantly cautious.

Last week, Celia Clinton Elementary went on lockdown after a threat was reported just outside.

"Actually, multiple people ran into the school and said, ‘There is a man out here, across the street, with a gun and he is firing shots,'" said TPS Campus Police Chief Gary Rudick.

Police determined the man was not targeting the school, but kept the lockdown in place for the safety of the children.

Lockdowns are common within Tulsa Public Schools. Rudick said the district has at least one or two in any given week, but since the Sandy Hook shootings, he said there have been more than normal.

"We've had a lot of concern. People are scared," Rudick said.

Last Friday, Hale High School went on lockdown after a student handed out bullets to classmates.

Last Monday, another school was put on lockdown after a security guard mistook the sound of a nail gun for shots fired.

"I think we've had probably a couple of instances where we have gone on a lockdown, where we might not have gone to such extreme measures in the past," Rudick said.

But Rudick said schools have options and don't always have to go on full lockdowns.

The school's principal decides what action to take, based on the threat level.

At Celia Clinton, for example, the principal barely disrupted class.

"On a full lockdown all classroom doors are locked. You can't get into the classroom," Rudick said. "In that particular case, at Celia Clinton, they were allowed to go ahead and continue their class work. But in some cases, we would ask them to take cover in the room."

Either way, post-Sandy Hook, lockdowns will likely be more common than before.

"I hope parents understand that, because of the circumstances we find ourselves in, the response is going to be a little bit more extreme," Rudick said.

Rudick said it's the principal's decision whether or not to let parents know when their child's school has gone on lockdown, although he says they should always be notified if it was a full lockdown.

Right now, TPS does not have a mass-notification system that would notify parents immediately, but Rudick said that's something they'll likely be asking for soon.