St. Paul police are investigating a fire that they say was intentionally set at a black church, a department spokesman said Tuesday, though he said it's too early to suggest a motive.

The fire, which has spawned online speculation about its cause, broke out sometime after 5 p.m. on Sunday at New Hope Baptist Church at 711 Bradley St.

Police spokesman Steve Linders said that any time a place of worship is vandalized or attacked, police treat the crime as a possible hate crime. "So we're looking for anything that would lead us to believe that there was some kind of bias involved," he said. But he stressed that any motives behind the fire remain unclear.

The St. Paul Fire Department does not consider the incident a hate crime, according to Deputy Fire Chief Roy Mokosso, who added that witnesses have said "there was some child fire play involved."

"There is no indication that this arson targeted the church specifically," Mokosso said. He said damage from the blaze was mostly limited to a shed next to the church, along with some residual heat damage to the house of worship. No injuries were reported.

Firefighters managed to keep the blaze from spreading to the church, which was founded in 1952 and moved into its current location in 1998, according to its website.

The church's pastor, Runney Patterson Sr., posted a photo of the damaged shed to his Facebook page on Monday, with the caption: "It was arson — a hate crime!!!" The post has been shared dozens of times.

Linders said that even though police are investigating the blaze as arson, "we know that no accelerants were used, there was no incendiary device, there was no explosion."

He said police are interviewing potential witnesses and trying to track down any surveillance video of the incident.

Staff writer Paul Walsh contributed to this report.