OAKLAND, Calif. (AP) -- Police are investigating a fatal shooting just outside the Occupy Oakland encampment in Northern California and the apparent suicide of a military veteran at an Occupy encampment in Vermont's largest city.

The Oakland killing is further straining relations between local officials and anti-Wall Street protesters. A preliminary investigation into the gunfire Thursday that left a man dead suggests it resulted from a fight between two groups of men at or near the camp on a plaza in front of Oakland's City Hall, police Chief Howard Jordan said.

Investigators do not yet know if the men in the fight were associated with Occupy Oakland, but they are looking into reports that some protest participants tried to break up the altercation, Jordan said.

Burlington, Vt., police said preliminary investigations show a 35-year-old military veteran fatally shot himself in the head Thursday at an Occupy Wall Street encampment. The name of the Chittenden County man is being withheld because not all of his family has been notified.

He shot himself inside a tent in City Hall Park. Mike Noble, a spokesman for the Fletcher Allen Health Care hospital in Burlington, confirmed that the man had died. Noble said he could provide no other details.

Deputy Chief Andi Higbee in Burlington told reporters the shooting raised questions about whether the protest would be allowed to continue.

"Our responsibility is to keep the public safe. When there is a discharge of a firearm in a public place like this it's good cause to be concerned, greatly concerned," Higbee said.

That's also the feeling with some people in Oakland.

With opinions about the ongoing demonstration and its effect on the city becoming more divided in recent days, supporters and opponents immediately reacted to the homicide - the city's 101st this year.

Camp organizers said the attack was unrelated to their activities, while city and business leaders cited the death as proof that the camp itself either bred crime or drained law enforcement resources.

Mayor Jean Quan, who has been criticized by residents on both sides for issuing mixed signals about the local government's willingness to tolerate the camp, issued a statement Thursday calling for the camp to shut down.

"Tonight's incident underscores the reason why the encampment must end. The risks are too great," Quan said. "We need to return (police) resources to addressing violence throughout the city. It's time for the encampment to end. Camping is a tactic, not a solution."

For their part, protest leaders said the shooting involved outsiders and was only connected to their ongoing protest of U.S. financial institutions to the extent that poverty breeds violence.

"This one heinous immoral crime should not overshadow all of the good deeds, positive energy and the overall goals that the movement is attempting to establish," Khalid Shakur, 43, who has a tent in the encampment, said.

Before the shooting, protesters were planning to have a party to commemorate the encampment's one-month anniversary with music, dancing, a slide show and donated cakes. Instead, they opened a microphone for participants to talk about where the movement is headed.

"It's not a celebration anymore, but a period of reflection," said Leo Ritz-Barr, a member of Occupy Oakland's events committee.

John Lucas, 52, part of an Occupy Oakland medic team, said a fistfight involving several men preceded the gunfire.

"Several people went after one guy, and the group got larger, and they beat him and he ran," Lucas said. "There were six or seven shots. Everyone starts running ... and there was another shot."

Lucas said he and other medics rushed to the wounded man and tried to tend to him until paramedics arrived.

"He was not breathing and there was no heartbeat," he said. "We started CPR."

Jordan said the victim was hit by one bullet and he was pronounced dead at a hospital.

No suspects have been identified, said Jordan, who asked people participating in the protest who may have taken photographs or video that captured the shooting to contact authorities.

The violence came a day after a group of Oakland city and business leaders held a news conference demanding the removal of the encampment, saying it has hurt downtown businesses and has continued to pose safety concerns.

Councilman Larry Reid said that even if the men involved in the slaying were not regular participants in Occupy Oakland, the large crowds and attention the protest has drawn also has invited weapons and brawls. The camp, which has about 180 tents, sits in the middle of the plaza and is ringed by a transit station and ground-floor shops.

"We did have a shooting (near the plaza) once before, a couple shootings around some nightclubs but not right here in front of City Hall because this is attracting a totally different element to our downtown area," Reid said. "This is a public space, and people have a right to enjoy it."

Shake Anderson, an Occupy Oakland organizer who has slept at the camp since it was erected exactly a month ago, said the man who was shot could not be associated with the protest because he did not recognize him. Just before the shooting, a group of strangers ran into the encampment as if they were looking for someone, Anderson said.

"The person on the ground was not part of the occupation," Anderson said.

---

Associated Press writer Dave Gram in Burlington, Vt., contributed to this report.

© 2011 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed. Learn more about our Privacy Policy and Terms of Use.