MANILA, Philippines -- A gunman stormed a casino in the Philippine capital and torched gambling tables in the crowded space, creating a choking level of smoke that killed at least 36 people, authorities said. The gunman stuffed a backpack with casino chips before he fled but was found dead in an adjacent hotel early Friday of an apparent suicide, bringing the total death toll to 37.

The Bureau of Fire Protection Services said it appeared many died of suffocation. Earlier reports indicated several dozen more were injured in the chaos and panic that followed after the gunman torched the gambling tables and stuffed a backpack with casino chips and tried to flee.

A guard was shot during the melee but survived.

Get Breaking News Delivered to Your Inbox

The Philippine national police chief Gen. Ronald dela Rosa says there is no concrete evidence the attack is terrorism and that robbery may have been a motive. Authorities have reviewed CCTV footage from the scene and the lone gunman "was not hurting anyone."

Smoke rises from the Resorts World Manila complex early June 2, 2017, in Manila, Philippines. AP

Metropolitan Manila police chief Oscar Albayalde said the English-speaking suspect was found dead with his rifle on the fifth floor of the Resorts World Manila complex. Dela Rosa described him as "white, with a mustache" and about 6 feet tall.

Police are searching the suspect's car, parked on the second floor. Before the attack, he got out of the car and entered the building with his rifle.

Dela Rosa said security footage showed the gunman ignoring a security guard who tried to question him at the entrance to the complex. He did not hurt the guard but went straight to the gambling area, dela Rosa said.

He said it seemed like the gunman was focused on the gambling table and stealing chips. The suspect shot an LED monitor and set ablaze gambling tables by pouring gasoline on them.

The suspect took 113 million pesos ($226,000) worth of gambling chips, which were in a bag he was carrying and later found in a toilet.

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.

Earlier on Thursday, Resorts World Manila tweeted that it's "currently on lockdown following reports of gunfire from unidentified men."

Resorts World Manila is currently on lockdown following reports of gunfire from unidentified men. — Resorts World Manila (@rwmanila) June 1, 2017

Later, company Chief Operating Officer Stephen Reilly told reporters that security operations were ongoing. Reilly said all guests had left the complex and were believed to be safe.

Resorts World Manila released an official statement to CBS News describing it was a sad day.

"The company has extended medical assistance to the 54 individuals who were taken to nearby hospitals," it read. "It is with deep regret that we have been informed of several casualties, the number and identities of whom have yet to be determined."

"This cowardly act of a deranged mind will not defeat the spirit on which Resorts World Manila was built," it added. "With your prayers, we will overcome this tragedy."

Dela Rosa said the gunman would have shot all the people gambling if terror had been the motive.

Abayalde says either the suspect lost in the casino and wanted to get his money back, or went "totally nuts."

The security guard was shot in the waist by the gunman and about 75 others suffered mostly minor injuries such as bruising as they stampeded to get out, said police officer Jeffrey Francisco.

Police said there was no indication any hostages had been taken by the lone gunman.

An injured hotel guest is seen outside of a hotel after a shooting incident inside Resorts World Manila in Pasay City, Metro Manila, Philippines, on Fri., June 2, 2017. Reuters

Philippine police rushed to the complex and were reportedly fired upon at the commercial center, where whitish smoke began billowing from an upper floor.

Witnesses also reported seeing injured people, including a SWAT member.

"I heard many, many gunshots," Julio Silva, a witness who managed to dash out of the mall complex, told DZMM radio network.

Ronald Romualdo, a maintenance worker at Resorts World, said he and his colleagues heard gunshots and saw people smashing the windows on the second floor and third floor to escape.

"We took out a ladder to save them. We were able to save many of them," he said. "But one woman I was trying to save fell from the second floor. ... I could not carry her." He said the woman was not moving afterward, but he didn't know what happened to her.

The company said it was working with the national police to ensure the safety of its guests.

"We ask for your prayers during these difficult times," the company said.

In Washington before announcing that the U.S. was pulling out from the Paris climate agreement, President Trump called the incident a "terrorist attack" and said he was closely monitoring the situation.

"It is really very sad as to what's going on throughout the world with terror," Mr. Trump said during the nationally televised announcement from the White House Rose Garden.

A security guard stops photographers from entering the vicinity of Resorts World Manila after gunshots and explosions were heard in Pasay City, Metro Manila, Philippines, on Thu. June 2, 2017. Reuters

The U.S. State Department urged people to avoid the area.

#Manila #Philippines - reports of explosions/gunfire at Resorts World Manila, near the Manila Intl Airport. Avoid area & monitor local news. — Travel - State Dept (@TravelGov) June 1, 2017

A Filipino operative for the Islamic State of Iraq and Syria (ISIS), in a quick communique, immediately took responsibility for the attack.

The SITE Intelligence Group, a U.S. terrorism monitor, said a Filipino operative linked to the Islamic State of Iraq and Syria who provides daily updates on an ongoing Muslim militant siege in the country's south claimed that "lone wolf soldiers" of ISIS are responsible for the attack.

An English message by the operative was distributed across several pro-ISIS Telegram chat groups, SITE said. According to SITE, he wrote: "The lone wolf soldiers of Khilafah attack the heart of Kufar the city of Manila in Resort World."

Friday's incident happened while Philippine troops are struggling to end the bloody siege by hundreds of extremists aligned with ISIS in the southern city of Marawi.

Defense Secretary Delfin Lorenzana told a news conference earlier in Manila that about 500 militants, including foreign fighters, joined the siege of Marawi, a mosque-studded city that is the heartland of the Islamic faith in the southern Philippines.

About 50 to 100 militants were putting up the strongest stand in buildings across a bridge from Marawi's city hall, where hundreds of reinforcement troops were deployed. Snipers and buildings that obstructed cannon fire were making it difficult for troops to end the siege, said Lorenzana, who had wanted to end the crisis by Friday.

A total of 120 militants have been killed in the fighting since May 23, when a failed government raid to capture one of Asia's most-wanted militants, Isnilon Hapilon, triggered the siege of the city by the rebels. Twenty-five of the dead militants have been identified as Filipinos, according to military officials. Eight others were foreign fighters, including a Chechen, a Yemeni and several Malaysians and Indonesians, Lorenzana said.

President Rodrigo Duterte said he ordered troops to "wipe them out, everyone."

"If you shoot him in the head, shoot him again in the heart to be sure," the tough-talking Duterte said in a speech.

At least 25 soldiers, five policemen and more than 24 civilians have been killed in the clashes, Lorenzana said.