MANILA, June 2 (Xinhua) -- At least 37 bodies, including that of a gunman, were found inside a Manila casino hotel that was set on fire by the attacker, the Philippine police said on Friday.

The gunman killed himself hours after he stormed the Resorts World Manila and plunged the hotel into chaos around the midnight Thursday.

Police said 54 others also sustained minor injuries in the melee.

Philippine security officials ruled out terrorism, saying it was a case of a botched robbery by a "deranged" man.

"Some of the bodies were found inside the casino on the second floor. Some of them were found inside the comfort room on the casino," Southern Police District chief Tomas Apolinario told CNN Philippines.

He said they were still determining whether the dead were casino players or employees. Earlier report put the death toll at 34.

None of the dead sustained gunshot wound, the police official said, adding that they died of suffocation. "I think the fire quickly spread because the suspect used either gasoline or kerosene to start the fire," he said.

The gunman, who opened fire and burned part of the casino, apparently killed himself, according to the police.

Based on initial report, Apolinario said the suspect sustained an "exit gunshot wound" in the head.

"The way the body was found has rifle pointing at his chin, indicating he set himself on fire and he shot himself," he said.

There were still areas that could not be accessed because of the toxic fumes, he said. "As far as danger and threat are concerned the building is already cleared," he said.

He said the police "are conducting continued investigations into the incident and ascertain the identity of the suspect."

"We are still investigating if he has accomplice in committing the crime but initial reports and evidence point that the suspect was alone," Apolinario said.

Earlier on Friday, Philippine National Police (PNP) Director General Ronald Dela Rosa also dismissed the shooting in Resorts World Manila as a terror attack, saying the lone gunman who carried out the attack only tried to steal green chips from the casino.

"It's too early to tell but so far as far as we are concerned there was no indication the IS-affiliated militants were behind the shooting," Dela Rosa said.

"As far the PNP is concerned we cannot yet attribute this to terrorism. This is not an act of terrorism," he said.

He said the gunman parked his car at the second floor of the building, started firing in the air and burned some tables before entering the storage room.

"He was also carrying a liter of petrol in his backpack which he used to set tables on fire," Dela Rosa said.

Resorts World Manila is an integrated resort located in Newport City opposite the Ninoy Aquino International Airport Terminal 3 in Pasay City.

The attack came as the administration of President Rodrigo Duterte battled with militants in Marawi City in southern Philippines. Daily clashes continue to break out as militants linked to Islamic State attacked the city on May 23.