SAO PAULO - A gunman shot and killed four people at a church in Brazil on Tuesday before turning the gun on himself, according to local media.

The shooting took place at the Campinas Cathedral in Sao Paulo state as a midday mass was in progress, a spokesman for the local fire department told Globo TV news.

The gunman was armed with two weapons and fired at least 20 times before police confronted him and he committed suicide in front of the altar.

Authorities said they didn't know the motive behind the mass shooting, but it appeared the perpetrator had no specific target.

"We think he was shooting at random, without looking for a clear target," the secretary of security in Campinas, Luis Baggio, told the TV network.

Surveillance cameras showed the man entered the church like any other worshipper and sat in the back for a few minutes before getting up and firing his gun, a 9 mm handgun used by security forces, Baggio said.

Another four people were injured and taken to hospitals.

Eyewitness Pedro Rodrigues, 66, said he ran out of the building when he heard shots and realized what was happening.

"The attacker entered and began shooting at a couple, and then continued firing in all directions. But I managed to get out. I'm very lucky to be alive," said Rodrigues.

The shooting, which was rarely seen in the South American country, has shaken residents of Campinas, a city 100 km west of the state capital Sao Paulo.

The Diocese of Campinas issued a statement asking for peoples' prayers at this "very painful time."