Resorts World Manila, in the southwestern part of metropolitan Manila near Ninoy Aquino International Airport, said on Twitter early Friday that it was working closely with police to ensure the safety of employees and guests, adding, "We ask for your prayers during these hard times".
The national police chief said the gunman apparently barged into a room at the 5th floor of the Maxims hotel connected to the mall and casino, laid on the bed, blanketed himself, doused himself with gasoline then set himself on fire.
The PNP Chief said it is possible that the suspect needed money badly and could have lost a lot in the casino.
The attacker also ransacked a room and stole gaming chips, Philippines National Police Chief Ronald Dela Rosa told CNN Philippines. Gunshots were fired but were not aimed at people in the room, he added.
Earlier, authorities said 35 dead victims were found in the casino area in Resorts World Manila after a lone gunman fired shots and set fire to gambling tables in the early hours of Friday morning.
It was not clear how the gunman smuggled gasoline and an assault rifle into the crowded casino or what prompted dela Rosa to cast doubt on terrorism so quickly.
The man left the room and went upstairs to the hotel section, but left the backpack, according to Dela Rosa. But police later said he appeared to be Filipino. The gunman fled with $2 million in stolen casino chips, then forced his way into a room in an adjoining hotel and killed himself.
"We have no official information as to the identity or affiliation of the persons responsible for this attack", the firm said in the hotel's official Twitter account.
Taiwan's foreign ministry said four people from Taiwan were among those killed, and South Korea said one of its citizens had died, apparently after a heart attack. About 70 people in total were injured.
"The hotel security was rattled, when a female security saw him (referring to the suspect) she ran away instead of calling immediately for assistance".
Police cordoned off the area near the Ninoy Aquino International Airport shortly after the attack began, according to the AP.
"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.
Numerous victims are believed to be women and are thought to have suffocated from smoke inhalation as crowds battled to escape the venue.
But Dela Rosa said the gunman "would have shot at people or triggered a bomb" had he been a terrorist. "I don't know if she is still there".
ISIS have claimed responsibility for the gunfire at the popular tourist destination.
It is really very sad as to what is going on throughout the world with terror.
President Donald Trump said he was "closely monitoring the situation" and would continue to provide updates, CBS News reported.
The police chief confirmed his original statement to the AP that there is "no concrete evidence that the attack was terrorism" - despite President Trump's opening remarks while announcing the USA withdrawal from the Paris accord on climate change.