People ran screaming out of Resorts World Manila, which is across a road from one of the main terminals of the Philippines’ international airport, according to television footage.
“Resorts World Manila is currently on lockdown following reports of gunfire from unidentified men,” the company said on its Twitter account.
“The company is working closely with the Philippine National Police to ensure that all guests and employees are safe.”
Daesh said “lonewolf soldiers” from its group carried out the attack, according to the SITE Intelligence Group that monitors terrorist organisations.
There were no immediate reports of fatalities or injuries.
Police surrounded the complex following the reports of the gunfire, which occurred just after midnight.
“I was about to return to the second floor from my break when I saw people running. Some hotel guests said someone yelled ‘ISIS’,” Maricel Navaro, an employee of Resorts World, told DZMM radio.
“Guests were screaming. We went to the basement locker room and hid there. People were screaming, guests and employees were in panic,” Navaro said.
“When we smelled smoke, we decided to go for the exit in the carpark. That’s where we got out. Before we exited, we heard two gunshots and there was thick smoke on the ground floor.”