In separate cases, two men were collectively sentenced to 25 years in prison for attempting to help the Islamic State terror group, the Justice Department announced Tuesday.

Leon Nathan Davis of Georgia was sentenced to 15 years in federal prison; Miguel Moran Diaz of Miami was sentenced to 10 years.

Davis, 37, of Augusta, Ga., was found guilty of attempting to provide material support to the Islamic State. He will be subject to lifetime supervision after his release.

The Justice Department said Davis planned for more than a year to join Islamic State on the battlefields in Iraq and Syria.

Meanwhile Diaz, 45, was sentenced for being a felon in possession of a firearm. His prison term will be followed by three years of law-enforcement supervision.

Diaz "was an armed, convicted felon who harbored sympathies for the Islamic State of Iraq and Syria," George Piro, the FBI agent in charge, said in a Justice Department statement issued Tuesday. "He called himself a 'lone wolf' for 'ISIS.' This is not a scenario where law enforcement can afford to wait and see what happens next."

Using an Arabic alias, Diaz posted a picture of himself with a gun on Facebook and later told an FBI source that he planned a shooting spree in which he would leave behind shell casings with the letters "ISIS" etched into them, according to the court record.