A resort in Manila was placed on lockdown early Friday after witnesses reported hearing gunfire and explosions at the mall, casino and hotel complex in the Philippine capital.
"Resorts World Manila is currently on lockdown following reports of gunfire from unidentified men," the resort posted to its Twitter feed.
The resort 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 resort said.
Philippine policemen have not given details about the incident but have begun cordoning off the area near the Ninoy Aquino International Airport.
The U.S. State Department urged people to avoid the area.
In Washington, President Trump was aware of the situation and being provided updates by his national security team, White House press secretary Sean Spicer said on Twitter, minutes before the president was set to make an announcement about the Paris climate agreement.
Friday's incident happened while, in the southern part of the country, Philippine troops are struggling to end a bloody siege by hundreds of extremists aligned with the Islamic State of Iraq and Syria, or ISIS.
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.
