An Army veteran is accused of planting an improvised explosive device (IED) at a Veterans Affairs hospital in Florida, officials said.

Mark Edward Allen, 60, is charged with possession of unregistered explosive devices after the FBI said he left an IED at a Veterans Affairs hospital in the Bay Pines area near St. Petersberg, and authorities found another IED in his home, according to the U.S. Attorney’s Office for the Middle District of Florida.

Allen is being held at the Pinellas County Sheriff's Office, and made his first court appearance on Tuesday. If he is convicted, he faces up to ten years in federal prison, according to the attorney general's office.

A criminal complaint said hospital staff called the Tampa Police Department and the FBI on May 29 after finding what they thought was an IED on the property.

Mark Edward Allen Pinellas County Sheriff's Office

When officers arrived, they rendered the device safe and then inspected it to find it was made of "a 9-volt battery, electrical wires, an improvised initiator, a clothespin switch, and a pyrotechnic-type powder that can cause an explosion," according to a criminal complaint.

Two days later, Allen's wife called police to report he made a bomb in his home. She loaded it into her trunk while he was sleeping, and brought it to a friend's house "because she was scared," according to the complaint.

Bomb technicians responded to the friend's home, and after inspecting the IED, "determined that the St. Pete IED and the VA Hospital IED likely came from the same person," the complaint said.

Surveillance footage also showed Allen placing the IED at the VA hospital. His wife identified him in additional surveillance footage that showed him coming out of a Wawa across the street from the hospital.

Allen's wife also told investigators that her husband is an Army veteran who frequently goes to the Bay Pines VA hospital and had appointments there during the week of May 27, the criminal complaint said.

Neither of the "destructive devices" were registered in the National Firearms Registration and Transfer Record, as required by law, the complaint said.