An alleged active shooter intent on attacking a Michigan church on Sunday was shot and killed by a security guard, authorities said.

The shooting unfolded around 11:15 a.m. local time at the CrossPointe Community Church in the Detroit suburb of Wayne, according to the Wayne Police Department.

Law enforcement sources said the suspect drove his Nissan truck into the church and opened fire, ABC Detroit affiliate WXYZ reported.

The Wayne Police Department confirmed on Facebook that the suspect was shot and killed by a security guard at the church. At least one victim was shot in the leg during the attack, according to police.

A bomb-sniffing dog was brought to the scene by the Michigan State Police and a police bomb squad was also brought to the scene, according to officials, but there was no immediate confirmation from police that explosives were involved in the incident.

As police investigated a motive for the attack, the FBI said it was sending agents to Wayne to help in the investigation.

“Our leadership and support teams are on the ground, at the scene, in Wayne, Michigan providing assistance and investigative support,” FBI Deputy Director Dan Bongino said in a statement.

The church shooting came during a heightened threat environment across the country following the U.S. attack overnight in Iran that destroyed or severely degraded three of Iran’s nuclear facilities, according to White House officials.

Acknowledging the heightened threat environment, Homeland Security Secretary Kristi Noem said in a statement that “it is our duty to keep the nation safe and informed, especially during times of conflict.”

“The ongoing Israel-Iran conflict brings the possibility of increased threat to the homeland in the form of possible cyberattacks, acts of violence, and antisemitic hate crime,” Noem said.

The attack in Wayne came in the wake of a public bulletin the Department of Homeland Security issued after the U.S. strikes in Iran, warning that “low-level cyber attacks” against U.S. targets “are likely” and that extremists inside the U.S. would be more likely to turn to violence if Iranian leadership calls for such retaliation.

The bulletin further urges the public to report any suspicious activity.

It was not immediately known if the church attack has any connection to the U.S. attack on Iran’s nuclear facilities.

The attack occurred about a half-hour after Sunday-morning services at CrossPointe Community Church started, according to police.

Officers arriving at the scene quickly evacuated the church after learning that a security guard stopped the attack by shooting and killing the suspect, according to police.

The suspect’s name was not immediately released. The security guard was also not immediately identified by authorities.

ABC News’ Luke Barr, Pierre Thomas, Mariama Jalloh and Victoria Arancio contributed to this report.

This is a developing story. Please check back for updates.