An explosion that tore a hole in the side of a church and injured 33 people was caused by a bomb, federal authorities said Monday.

Sunday's explosion at the First Assembly of God Church was the second church bombing in five months in the same county."We have determined that it was a bomb. It is an explosive," special agent Jerry Singer of the federal Bureau of Alcohol, Tobacco and Firearms said Monday. Residue from the explosive will be sent to a laboratory for examination, he said.

The FBI has joined in the investigation, Singer said.

Singer said there is no evidence in hand that would tie this explosion to a bomb that killed a 46-year-old church volunteer Dec. 30 at a church in Oakwood, about 10 miles to the west. There have been no arrests in that incident.

The ATF laboratory in Rockville, Md., will examine the Danville explosives for any resemblance to the Oakwood bomb and others throughout the country, Singer said.

"There is no indication that the (Danville) church has had any prior threats or problems," he added.

Singer would not provide details on the Danville explosive except to say "it was a considerable amount of force."

The church, a wood frame and metal structure, was built in recent years in one of the more crime-ridden neighborhoods of this blue-collar city of 34,000 people.

The pastor, the Rev. Dennis Rogers, said Monday he knew right away it was a bomb because it smelled like gunpowder.

"Even while it was happening, I was saying to myself, was this a dream, is this really happening. Nothing can prepare you for this," he said.

Some 300 people were attending Sunday morning's service at the Danville church. Parishioners had just bowed their heads in prayer when the violent blast rocked the church and white smoke filled the sanctuary.

After scrambling through the smoke and debris, Betty Lawrence still had reason to express thanks that no one was killed.

"God did keep his hands on us," she said. "No one died."

Two girls, ages 14 and 15, were in serious but stable condition with head lacerations at a hospital in Urbana. Six others were listed in fair or stable condition in a Danville hospital. The 25 others were treated and released.

The force of the explosion shattered windows up to 100 yards away. Bits of glass and twisted metal littered the street.

"Honest to God, I thought it was a bomb in my garage," said Tasia Demos, who lives across the street from the church and heard the blast from her upstairs bedroom.

Rogers said Sunday's explosion was near the youth section and that many of the injured were teen-agers. The lights went out as smoke filled the building.

"I couldn't see," Rogers said. "The place was completely darkened by smoke. I told the people to move as quickly and quietly as you can out of the building."

Church members gathered afterward to pray "that anger would not rule, that we would not ask why, that we would move on," Rogers said.

Danville is 120 miles south of Chicago, near the Illinois-Indiana state line.