The suspect who was reportedly seen with a handgun tucked in his waistband, prompting a lockdown Thursday at a Manchester, N.H., high school is in custody, police told Fox News.

Sgt. Brian O'Keefe said the former student was seen entering West High School Thursday morning. He said the school was in lockdown as a precautionary measure and that "all kids are safe." 

Numerous police cars have surrounded the school in New Hampshire's largest city is about 20 miles south of Concord. It has about 1,300 students.

Further information was not immediately available. O'Keefe said he would provide more information as he gets it.

The Associated Press contributed to this report