An Ohio man who had expressed support for al-Qaida and a desire to kill American soldiers and told an undercover agent that he wanted to attack a Fourth of July parade in Cleveland was arrested on Sunday, authorities said.

FBI agents began investigating the man, Demetrius N. Pitts, 48, more than a year ago, after they discovered messages he sent on Facebook espousing anti-American views and a belief that Muslims “should always be prepared to fight.” But his desire for an attack became more clear during conversations in recent weeks with the undercover agent, federal officials said in an announcement Monday.

Pitts told the agent, who was posing as an al-Qaida sympathizer, that he wanted to set off bombs and launch attacks in multiple cities across the United States, starting with Cleveland on Independence Day, authorities said. It is unclear, however, if he had the capability of acting on his plans, the FBI added.

“I’m trying to figure out something that would shake them up on the Fourth of July,” Pitts said at a June 22 meeting with the undercover agent, according to a copy of a federal criminal complaint.

Pitts was arrested Sunday morning. He was charged with one count of attempting to provide material support or resources to a foreign terrorist organization, which carries a 20-year prison sentence if convicted.

Stephen Anthony, the special agent in charge of the FBI’s Cleveland field office, praised the work of the local police and federal agents in the investigation.

“Law enforcement cannot sit back and wait for Mr. Pitts to commit a violent attack,” Anthony said at a news conference Monday. “We don’t have the luxury of hoping an individual decides not to harm someone or get others to act.”

Anthony said that the investigation into Pitts, a U.S. citizen who also used the names Abdur Raheem Rahfeeq and Salahadeen Osama Waleed, started with the bureau’s office in Cincinnati, where Pitts used to live. Federal agents in Cleveland took over the case recently when Pitts moved to the nearby city of Maple Heights.

The FBI first became aware of Pitts in 2015 when, officials said, he sent a message on Facebook using the name Abdur Raheem Rahfeeq to an obscure California talk show, saying, “The USA will be destroy. Allahu Akbar.”

The undercover FBI agent was introduced to Pitts this year after he “expressed a desire to meet with an al-Qaida ‘brother,’” according to the criminal complaint. The agent and Pitts first met on June 15, and they discussed possible attacks and methods in a series of meetings that followed.

“Put bomb, bomb, bomb, bomb, bomb — anywhere you want around here, and level stuff around here,” Pitts said while discussing a hypothetical attack on military bases with the agent, according to court records. “I mean, just like how the Japanese hit Pearl Harbor.”

It was not clear whether Pitt was being represented by a lawyer. Relatives for Pitt could not be reached for comment.

While Pitts expressed a desire to launch an attack, according to the FBI, it was not clear whether he had the ability, resources or expertise to carry one out. In his conversations with the undercover officer, Pitts rambled, often incoherently, about seemingly improbable ways that he could hurt people, according to transcripts included in the criminal complaint.

He said he could chop up people with a machete and send their parts to a hog farm for pigs to eat. He said he could behead soldiers and toss their heads in front of military bases, forcing every base in America to shut down until the “heads stop spinning.”

Pitts talked of the possibility of hiding explosives in pipes under homes, placing explosives in chicken eggs for an attack in Philadelphia, and strapping bombs to toy cars that could be given as gifts to children at the parade in Cleveland.

But Pitts also said he had limitations. According to court records, he told the undercover agent that he would have difficulty buying vehicles for a car-bomb attack because he would need to show a driver’s license.

Anthony said that the FBI had “no information” that Pitts had traveled overseas to meet with al-Qaida or that he had access to explosives or weapons. “His precise ability to do specific things, again, we may never know,” he said.