Police are investigating a fire that hit a predominantly black church in St. Louis, Missouri, eyeing arson as the cause. The church was also vandalised.

The fire occurred before 2 a.m. on Tuesday at the Greater St. Paul Missionary Baptist Church in the Walnut Park East area in St. Louis.

Firefighters were called to the scene after a building alarm sounded, the Associated Press reports.

Police said they forced open the back door of the church and found graffiti written on the exterior of the building containing derogatory words for African-Americans.

The fire damaged an estimated $200,000 worth of property inside the church.

Pastor Titus Irving, head of the church which has about 200 members, said he is "heartbroken."

"I know the Lord will see us through this, but it tears your heart apart," he said.

He said the incident "just shows you the level of hate in our city," according to KTVI. "It's happening even across our country."

Irving said surveillance cameras captured the incident which showed two suspects. He suspects that the fire is connected to two acts of vandalism in churches in St. Louis. One was at the Eastern Star Missionary Baptist Church in May and another at the Memorial Baptist Church in June.

"This is just something that's evil, that God's going to turn into some good," said Associate Pastor Shirley Little, adding that she will pray that those responsible understand the damage they have caused.

Last October, a series of arson attacks at churches in St. Louis prompted a hate crime investigation by the police.

The police filed two counts of second-degree arson against David Lopez Jackson, who is in jail awaiting trial.

Pastor Irving said that despite the graffiti, he is not convinced that it was motivated by race.

"I'm not really believing it's racial. I just believe that it's hatred against the church at large," he said.