A commercial center in Manila was placed on lockdown early Friday after witnesses reported hearing gunfire and explosions at a mall, casino and hotel complex in the Philippine capital near its airport.

A guard was shot during the melee but survived, and more than 70 others suffered mostly minor injuries in a stampede to get away from the gunman, who was wielding an assault rifle and sent hundreds fleeing into the night.

In a press briefing Friday morning in Manila, Philippine police said the suspect was found dead of apparent suicide.

Metropolitan Manila police chief Oscar Albayalde says the English-speaking suspect was found dead with his rifle on the fifth floor of the Resorts World Manila complex.

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.

Abayalde says the guards at the door ran away after seeing the armed man.

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."

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 found in a bag he was carrying.

It was not clear how the gunman smuggled enough gasoline into the crowded casino to cause explosions and what prompted Dela Rosa to rule out terrorism so quickly.

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

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.

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.

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. It was not immediately clear if anyone was killed, or if the attack had concluded.

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

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.

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

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.