Resorts World Manila said on social media it was in lockdown and police were in control of the situation.
Manila: Gun shots and explosions rang out from an entertainment resort in the Philippine capital Manila early on Friday and local media reported armed men were inside the complex.
Resorts World Manila said on social media it was in lockdown and the local fire department said a blaze was burning on the second floor of one building.
"We are searching the area as much as we can, to make sure it is clear. I can confirm that shots were fired," a Resorts World official, Stephen James Riley, told reporters.
Asked how gunmen were able to enter the building he said: "That is not known at this time. We will investigate later."
Large numbers of police massed outside as smoke rose from the casino, hotel and shopping complex, a Reuters witness said. The complex is close to Terminal Three of Ninoy Aquino International Airport and an air force base.
Videos posted on social media showed people running from the resort as several loud bangs could be heard. Other footage, none of which could be immediately verified, showed apparently injured people being taken away by emergency services.
"We ask for your prayers during these difficult times," Resorts World said on Twitter.
Military spokesman Restituto Padilla said the police were in control of the situation and the army was monitoring closely.
A spokeswoman for the police National Capital Region, Kimberly Molitas, appealed to people not to spread social media posts coming from the complex.
"The operation is still ongoing," she said. "Let's keep the people inside Resorts World and our police safe."
Witnesses who spoke to radio stations said several gunmen were seen in the complex. News channel ANC said there were two gunmen, wearing masks and black clothes.
A casino worker from the third floor, named Julio, told DZMM radio he heard many gunshots and saw people running up the stairs from the second floor.
Ronald Romualdo, a maintenance worker at Resorts World, told the station he saw a woman fall from an upper floor while trying to escape. "Several people were injured," he said.
Citing witnesses, news channel ANC said a man had poured flammable liquid onto several gaming tables and set them alight.
The Philippines is facing a crisis in the south of the country, where troops have been battling Islamist rebels since May 23. President Rodrigo Duterte declared martial law on the southern island of Mindanao last week.
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