Before it was revealed an Iraq War Marine veteran was the perpetrator of a mass shooting and firebombing of a Michigan church, President Donald Trump denounced "another targeted attack on Christians" in America.

"I have been briefed on the horrendous shooting that took place at the Church of Jesus Christ of Latter-day Saints, in Grand Blanc, Michigan," Trump wrote on Truth Social. "The FBI was immediately on scene, and will be leading the Federal Investigation, and providing full support to State and Local Officials. The suspect is dead, but there is still a lot to learn.

"This appears to be yet another targeted attack on Christians in the United States of America. The Trump Administration will keep the Public posted, as we always do. In the meantime, PRAY for the victims, and their families. THIS EPIDEMIC OF VIOLENCE IN OUR COUNTRY MUST END, IMMEDIATELY!"

A man, 40, smashed a pickup into the church, opened fire, and set the building ablaze during a crowded Sunday service. He was chased and fatally shot by police. At least four people were killed and eight wounded, and authorities were searching the building ruins for additional victims.

The attack occurred about 10:25 a.m. local time while hundreds of people were in the building in Grand Blanc Township, outside Flint.

The man got out of the pickup with two American flags raised in the truck bed and started shooting, Police Chief William Renye told reporters. The attacker apparently used gas to start the fire and also had explosive devices, but it was not clear if he used them, said James Dier of the Bureau of Alcohol, Tobacco, Firearms and Explosives.

Authorities identified the shooter as Thomas Jacob Sanford, 40, of the neighboring small town of Burton. The FBI is leading the investigation and considered it an "act of targeted violence," said Ruben Coleman, a special agent in charge for the bureau.

Officers responding to the 911 call arrived at the church within 30 seconds, Renye said. After the suspect left the church, two officers pursued him and "engaged in gunfire," killing him about eight minutes later, the chief said.

People inside the church shielded children and moved them to safety during the attack, Renye said.

Investigators were searching Sanford's residence but authorities did not say what they found or provide any additional details about him, including whether he was a member of the church.

Sanford served in the Marines Corps from June 2004 through June 2008, working as an automotive mechanic and vehicle recovery operator, according to military records obtained by The Detroit News. He was deployed to Iraq from August 2007 through March 2008 and had the rank of sergeant.

It was the latest of many shooting attacks on houses of worship in the U.S. over the past 20 years, including one in August that killed two children during Mass at the Church of the Annunciation in Minneapolis.

It also was the second mass shooting in the U.S. in less than 24 hours. A man in a boat opened fire on a crowd in Southport, North Carolina, killing three and injuring five Saturday night.

Information from The Associated Press was used to compile this report.