The mother of a Massachusetts teenager says students on a school trip to the U.S. Holocaust Museum heard several gunshots before they were evacuated from the building.

Sandy Perkins says her daughter, Abigail, called her shortly after the shooting.

Abigail told her mother that some of her friends were very shaken, but all were otherwise fine.

The teens from Danvers, Mass., did not see where the shots were coming from before they were safely evacuated to buses outside the museum.

Authorities say at least two people were shot at the museum when a person walked in with a rifle.