Philippine President Rodrigo Duterte yesterday said that Islamic State militants were not behind the attack on a casino in the capital that killed at least 36 people, supporting a police assessment that it was merely a botched robbery.

The gunman who burst into the Resorts World Manila entertainment complex early on Friday, firing shots, setting gaming tables alight and killing dozens, all suffocating in thick smoke, had been labelled by a top lawmaker as a "lone wolf" terrorist.

"That is not the work of ISIS," Duterte, using an acronym for Islamic State, told reporters in Cagayan de Oro city where he was visiting troops. "The work of ISIS is more cruel and brutal, they would simply kill people for nothing."

Clips from the casino CCTV, which police and officials at Resorts World released yesterday, showed the gunman was firing shots at the ceiling and setting gaming tables and slot machines ablaze.

The gunman, whose identity remains unknown, was caught on camera purportedly stealing casino chips worth 113 million pesos($2.27 million) from a storage room before he was later found by security officers, who shot and wounded him during an exchange of fire.

Duterte's spokesman, Ernesto Abella, said on Friday there was no proof linking the casino attack to a protracted urban battle between government troops and Islamist militants in the country's south..

Meanwhile, scores of people ran to freedom through a terrifying gauntlet of military air strikes and Islamist gunmen Saturday, nearly two weeks after being trapped in a deadly battle for a Philippine city.

Marawi has been transformed into a warzone since hundreds of gunmen rampaged through the city on May 23.