The man behind Friday's deadly attack on a casino in the Philippine capital Manila has been identified as Jessie Carlos Javier, a 42-year old Filipino, police said on Sunday.

The gunman burst into the Resorts World Manila entertainment complex early on Friday, firing shots and setting gaming tables on fire. A total of 37 people died from smoke inhalation.

"He is heavily indebted due to being hooked on casino gambling," Manila police chief Oscar Albayalde told reporters.

"This is not an act of terrorism," reiterated Albayalde on Sunday, though ISIL has claimed responsibility through a report on its self-styled Amaq news agency saying its "fighters" carried out the attack.

Earlier on Saturday, Philippine President Rodrigo Duterte also said that ISIL was not behind the attack.