LETTERKENNY, Pa. — An explosion at an Army depot in Pennsylvania has left some workers injured, authorities said.

Letterkenny Army Depot officials say the blast occurred around 7:15 a.m. Thursday. They posted on social media that the "incident is contained" and won't affect depot operations or workforce safety elsewhere on the site. Officials say there is no suspicion of terrorist activity.

The Franklin Fire Company posted on its Facebook page that three burn victims have been transported via air to hospitals. Details about other injuries were not immediately available. Some people have been treated at the scene.

The depot, located 160 miles west of Philadelphia, or about 55 miles southwest of Harrisburg, employs about 3,600. The depot's website says work there focuses on air defense tactical missile ground support equipment, mobile electric power generation equipment, Patriot missile recertification and route guidance vehicles.

Depot staff members have been told to stay in their work areas until further notice.