(CNN) -- Thirty-five people have been killed in a Manila casino, following an attack in the early hours of Friday morning by a lone gunman who fired shots from an assault rifle and set fire to gambling tables.
An earlier report from Philippines police misstated the death toll as 36.
The victims, who did not appear to have been shot, are thought to have died of suffocation, Southern Police District Director Superintendent Tomas Apolinario said Friday. "Most of the victims were women who were found dead inside the bathroom," he added.
Thick smoke from fires set by the suspect delayed a search of the building, but officers later discovered them during clearing operations, National Capital Region Police Office (NCRPO) Director Oscar Albayalde said.
All of the bodies were found in Resort World Manila's casino area, he said. Of those killed, 22 were resort guests and 13 were staff. Another 54 people were injured. The gunman later killed himself.
Despite ongoing ISIS-affiliated militant activity in the southern Philippines island of Mindanao, authorities ruled out terrorism as the motive for the attack.
"This particular situation in Manila is not related in any way to a terrorist attack," presidential spokesman Ernesto Abella told reporters.
Manila police chief Oscar Albayalde told reporters that police think it's likely the suspect was a foreigner. "He looks Caucasian, he talks English, he's big and he's white, so he's probably a foreigner," he said.
How the attack unfolded
The armed suspect forced his way into the Resorts World Manila, an upmarket hotel and casino complex near the Ninoy Aquino International Airport, around midnight local time (Thursday ET).
Also known as RWM, Resorts World Manila is described on its website as the "first and largest integrated resort in the Philippines."
According to security footage viewed by police, the gunman entered via the parking lot. Police later searched a car and found registration information which they haven't made public.
The attacker walked straight into the building, past a lone security guard who panicked when she saw the suspect's automatic rifle, Albayalde said.
Reilly said only guards on the complex's perimeter are armed. Internal security officers don't carry weapons, and didn't try to engage the suspect, fearing escalation of the situation, he said.
Video of the scenes showed guests frantically running for the exits, the sound of gunshots and smoke coming from the upper floors of buildings.
The man ransacked a room and stole gaming chips, Philippines National Police Chief Ronald Dela Rosa said early Friday. He had stuffed chips totaling 113 million pesos ($2.3 million) in a backpack, but this had been recovered by police, he added.
Apolinario confirmed that during the incident the gunman had engaged in a "firefight" with casino employees.
Stephen Reilly, the resort's Chief Operating Officer, said the attacker was shot and wounded by security guards, and retreated into the hotel room where he eventually killed himself.
"We would like to extend our gratitude to our security team," Reilly said.
According to a statement from RWM, the gunman was found dead around 7 a.m. local time.
"He had taken his own life by setting himself on fire followed by a self-inflicted gunshot wound," the statement said. Police confirmed he had died in a room on the fifth floor of the Resort World Hotel.
CNN affiliate CNN Philippines reported he was found in the room, burned beyond recognition, next to a machine gun and a .380 caliber pistol.
Witness: 'I could smell some kind of smoke'
Hundreds of guests and employees rushed out of the resort hotel after the gunman began shooting on the second floor, hotel employees fleeing the scene told CNN Philippines.
Jay Dones, a witness on the scene, said some employees had told him a gunman fired shots in the air.
"One of the employees told me that the suspect began pouring the contents of the bottle on one of the tables and lit it on fire," Dones said.
Witnesses also told about hearing what sounded like explosions.
"I could smell some kind of smoke that came from an explosive device," said Tikos Low, who said he was in the resort's casino along with a few hundred other people when the attack began.
The resort was put on lockdown and heavily armed SWAT officers wearing bulletproof vests and body armor descended on the scene.
The gunman didn't appear to be firing at people, said PNP Chief Dela Rosa.
Airport locked down
All terminals at Ninoy Aquino International Airport were placed on lockdown because of the attack, according to Robert Echano with airport operations. The airport is about a mile away from the resort.
Later the airport returned to normal operations but was on heightened alert, an airport official said.
Security remains on "high alert" status, a statement from the airport said.
In Quezon City, one of the municipalities in metro Manila, Police District Director Guillermo Eleazar ordered all 12 police stations in the city to set up checkpoints and to maximize police visibility.
All mobile patrol units and tactical motorized units of QCPD were deployed to secure the city.
Following events in Mindanao, Philippines President Rodrigo Duterte suggested he might extend martial law through year's end or impose it nationwide, alarming critics. On Friday, Dela Rosa ruled out declaring martial law on the main island of Luzon, where Manila is located.