Story highlights Police say they believe the shooting was carried out by a lone gunman

An 18-month-old child is among the dead, they say

The mayor of a southern Philippine town, his wife and niece were also killed

Five people were wounded in the attack outside the airport terminal building

A gunman opened fire outside a terminal at Manila's main airport on Friday, killing the mayor of a southern Philippines town, two members of his family and a young child, authorities said.

Striking amid the bustle of pre-Christmas travel, the attack wounded five people and caused panic among passengers caught up in the chaos.

Gun crime and political violence occur with grim frequency in the Philippines. But the shooting Friday at Terminal 3 of Ninoy Aquino International Airport appeared particularly brazen.

Initial reports suggested the shooting may have been carried out by more than one attacker. But police said they believe a lone gunman sprayed bullets at the mayor and his entourage before fleeing on foot and being picked up by an accomplice on a motorcycle.

The dead include Ukol Talumpa, the mayor of Labangan, a town in the southern Philippines, and his wife and 28-year-old niece, said Supt. Jose Erwin Villacorte, director of the Manila region's Southern Police District.

An 18-month-old child, believed to have been struck by a stray bullet, was also killed, Villacorte said.

Authorities said the shooting took place around 11:20 a.m. at the terminal's loading bay, an area outside the airport's security screening of passengers. It was a busy time at the airport, which handles both domestic and international flights.

Police believe the mayor, who has reportedly survived previous assassination attempts, was the target of the attack, Villacorte said.

Talumpa and his family had flown from the southern Philippines to Manila, where they planned to spend the Christmas holidays, Villacorte said.

The mayor's security detail, at least one of whom was wounded, hadn't yet reclaimed their weapons after the flight, so they were unarmed when the attack took place, he said.

Jose Angel Honrado, the general manager of Manila International Airport Authority, said flights haven't been disrupted and the airport is operating as normal, except for the specific area where the shooting happened.

The people wounded in the attack have been taken to a medical center for treatment, he said.

Villacorte said police were still gathering information in their investigation into the case.

The official Philippines News Agency reported that Talumpa had previously survived an assassination attempt in Manila in 2010 and a grenade attack in 2012 in Zamboanga del Sur, the province where Labangan is situated on the southern island of Mindanao.

The Philippines is plagued by political violence. Some political clans control private armies.

The deadliest outbreak of politically motivated violence in recent history took place in 2009 in Maguindanao province on Mindanao. The wife and sister of a political candidate and 30 journalists were among the dozens of victims who were shot and buried in a mass grave.

Philippines authorities say there were more than 1.2 million registered firearms in the country last year and estimate there were another 600,000 unlicensed firearms in circulation nationwide.

The Philippines is currently estimated to have a population of about 106 million people.