Washington CNN  — 

An American citizen was arrested Friday morning in a Cleveland suburb after authorities say he pledged support to ISIS and tried to purchase an AK-47 with the intent of carrying out an attack on the United States.

The Justice Department said in a press release that Amir Said Abdul Rahman Al-Ghazi, 38, was arrested in North Olmstead, Ohio. Al-Ghazi, who is a convicted felon, allegedly possessed a gun and trafficked marijuana.

The arrest was the third this week of an American attempting to aid the terrorist organization. Authorities arrested young men in New York and New Jersey earlier this week for similarly conspiring to provide ISIS, also known as ISIL, with material support.

“Today’s charges are a stark reminder that the radical and dangerous philosophies espoused by groups such as ISIL can be spread in our community through computers and social media,” U.S. Attorney Steven D. Dettelbach said in a statement. “Law enforcement will remain vigilant in combating violent extremism in all its forms.”

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According to the complaint, Al-Ghazi changed his name from Robert McCollum earlier this year and is alleged to have pledged his support to ISIS and Abu Bakr Al-Baghdadi in 2014 via social media. Over the past year, Al-Ghazi made multiple statements trying to persuade others to join ISIS.

Al-Ghazi also allegedly tried to make propaganda videos for ISIS. He was taken into custody after he tried to purchase an AK-47 from an undercover FBI employee, the release said.

Several details, including Al-Ghazi’s prior felony convictions, where he was being held and whether he had an attorney, were not immediately clear. Messages left with the Justice Department early Friday evening were not immediately returned.

The FBI’s Cleveland Division’s Joint Terrorism Task Force is investigating the case. The U.S. Attorney’s Office of the Northern District of Ohio and the National Security Division’s Counterterrorism Section are prosecuting the case.

The FBI is increasingly monitoring communication between ISIS and potential American recruits after an ISIS-inspired shooting in Garland, Texas, last month.