Three others were wounded in the attack, and the gunman was also injured and receiving medical care, according to the local NBC affiliate.

The meeting of town supervisors in Ross Township, in the eastern US state's Monroe County, was slated to begin at 7:00 pm local time (2300 GMT). Just 23 minutes later, emergency calls started coming in, the broadcaster said.

The Pocono Record local paper reported that an official had tackled the shooter and shot him with his own weapon. The shooter was reportedly conscious when he was taken away on a stretcher.

Chris Reber, a reporter for the newspaper who was at the meeting, said the shooter fired through the walls, sending clouds of plaster into the room where around 15 people were seated on folding chairs.

"I heard more than 10 shots. It was automatic, like a string of firecrackers," he said, according to an account published on the newspaper's website.

After crawling out through a hallway and fleeing into the parking lot, Reber said he saw the gunman emerge from the building.

"The gunman was this guy wearing a blue Hawaiian shirt. I saw him go back out to his car -- a silver Impala -- and get another gun," Reber said.

Monroe County police confirmed the death toll but declined to comment on a possible motive for the attack.