Washington (AFP) – Michigan’s governor on Monday asked Americans to “lower the temperature” after the latest violence in her state, as authorities search for a motive in a Mormon church attack the day before.

“We still are in the process of clearing out that church, but at this time everyone is accounted for,” Grand Blanc police chief William Renye said as he confirmed a final toll of four victims killed and eight injured in Sunday’s violence.

Police in the northern US state said the shooter first rammed the church with his vehicle before opening fire with an assault rifle, and then set the building on fire.

He was killed by police in the parking lot minutes later.

Images in the aftermath of the Church of Jesus Christ of Latter-day Saints in Grand Blanc, near Flint, showed most of the building reduced to ashes.

FBI special agent for Michigan Reuben Coleman called the incident “an act of targeted violence” but declined to specify who or what the target was.

“We are continuing to work to determine a motive,” Coleman told a press conference.

Democratic Governor Gretchen Whitmer said that "at this juncture, speculation is unhelpful and it can be downright dangerous.

“So, (I) just ask that people lower the temperature of rhetoric.”

Sunday’s attack comes a month after a shooting at a Catholic church and school in neighboring Minnesota, in which two children were killed while attending Mass, and several were severely wounded.

As partisan divisions deepen, political violence has become more frequent in the United States.

President Donald Trump called Sunday’s violence “horrendous” and said it was “yet another targeted attack on Christians in the United States of America.”