A protester sets himself on fire outside the Israeli consulate in Atlanta.

A protester set himself on fire outside the Israeli consulate building in Atlanta on Friday afternoon, in what police described as “likely an extreme act of political protest.”

A security guard tried to intervene but was unsuccessful, officials said. The protester suffered third-degree burns to the body and the guard was burned on his wrist and leg. Both were taken to Grady Memorial Hospital, where the protester was in critical condition.

Officials did not identify the protester, but said at a news conference Friday that the person appeared to act alone and that a Palestinian flag “was recovered from the site and was part of the protest.” The fire chief, Roderick M. Smith, said there was evidence that gasoline was used as an accelerant.

The city’s police chief, Darin Schierbaum, said officials did not believe there was “any connection to terrorism.” The building, in Atlanta’s Midtown neighborhood, houses the consulate and several other offices.

“It appears the focus was outside the building. I am not aware of any attempt to enter the building,” Chief Schierbaum said, adding: “I have met with the Consul General. The staff is safe. All residents of this building are safe.”

The Atlanta FBI said it is aware of the incident and is working with local law enforcement. Chief Schierbaum said he was not aware of any credible threats against the building.

“It is tragic to see hatred and incitement against Israel manifested in such a horrific way,” Anat Sultan-Dadon, Israel’s consul general in the southeastern United States, said in a statement on Friday. “The sanctity of life is our highest value. Our prayers are with the security officer who was injured trying to prevent this tragic act.”