Pregnant woman among eight killed in Pennsylvania shooting

A pregnant woman, children and other relatives are among eight victims gunned down by a man at a home in Pennsylvania.

Erie Police Chief Rick Lorah said the 45-year-old man was related to seven of the victims, while the eighth was a friend of the pregnant woman.

Video and audio evidence recovered by investigators included muffled gunshot sounds coming from inside the home just before two "distressed" women arrived and began pounding on the door shortly before 5pm on Friday, local time, Mr Lorah said. 

The gunman then came out and shot them as they ran toward him, before returning inside.

Police arrived to find the two women dead outside.

After deploying a drone and robot, police went inside the home and found the bodies of a five-year-old boy; a one-year-old girl on the first floor; two more women and two young men in a stairwell; and the shooter on the second floor.

"Out of respect for the victims and the families, I will not discuss the details of what our officers encountered inside that home," Mr Lorah said at a news conference.

"But I want our community to understand the gravity of what happened and the profound impact this tragedy has had on those involved and on our community as a whole."

Mr Lorah declined to discuss motive but said investigators would talk to other relatives and examine the mobile phones of the women who were killed outside the home.

"They knew something was going on at that house,"

he said.

"We have to figure out what that is."

Mr Lorah said officers arrived within minutes of receiving an alert via ShotSpotter, a controversial gunshot detection system that relies on artificial intelligence and a network of microphones to identify gunshots.

No additional shots were fired after that.

"Sounds that may have been mistaken for gunfire came from flashbang devices, chemical munitions, used by SWAT officers," he said.

Pennsylvania Governor Josh Shapiro said he offered his administration's "full support" to Erie Mayor Daria Devlin, who spoke directly to the victims' families during the news conference.

"I am so deeply sorry. What happened to you was horrific, and there is nothing that any of us can say today that will make this any easier," she said. 

"But you do need to know that our entire community is with you, we're grieving with you. And we are here to support you."

District Attorney Elizabeth Hirz urged the public to refrain from speculation as the investigation continued.

"Please do not allow rumours, speculation or unverified information to add to the pain that these families are already experiencing,"

she said.

Erie is about 190 kilometres north of Pittsburgh.

Speaking at a campaign rally outside Philadelphia, Mr Shapiro mentioned both the Erie killings and the shooting of two Philadelphia police officers early Saturday.

"Today has been a dark day across this commonwealth," he said.