Policemen stand guard near evacuated employees of a hotel near a situation at a Resorts World building, in Pasay City, Metro Manila, Philippines June 2, 2017. Photo Credit: Reuters

Evacuated employees and guests of hotels stand along a road and watch as smoke billows from a Resorts World building in Pasay City, Metro Manila, Philippines June 2, 2017. Photo Credit: Reuters

A security guard stops photographers from entering the vicinity of Resorts World Manila after gunshots and explosions were heard in Pasay City, Metro Manila, Philippines June 1, 2017. Photo Credit: Reuters

Resorts World Manila was put on lockdown after the incident, which happened shortly after midnight local time (16:00 GMT).

Swat teams were deployed to the scene, with people fleeing the hotel in panic.

The Philippines police chief said they did not believe it was a terror attack.

Ronald dela Rosa said a lone gunman had entered the gaming area at Resorts World, fired at a television, and set some gambling tables on fire.

Gunshots were fired, he said, but were not aimed at people in the room.

He admitted that the gunman had not been found.

"We have cleared the rooms [on the floor of the hotel where the gunman was last seen], but we don't see where he is," Mr dela Rosa said.

Resorts World Manila features multiple hotels and bars, as well as a shopping centre and casino.

The police chief told local radio station DZMM the gunman had filled a bag with casino gambling chips, and that the incident may have been an attempted robbery.

He warned that Islamic State militants might falsely claim to be behind it to further their propaganda.

"We cannot say this is an act of terror ... he [the gunman] did not hurt anyone," the police chief said. "If you are a terrorist you will sow terror."

He added that nobody had been shot and that the only injuries were from smoke inhalation, or the stampede that formed as people tried to escape.

Many witnesses took the incident for a militant assault.

Maricel Navaro, a Resorts World employee, told DZMM radio he had returned from his break to find people fleeing in panic.

"Guests were screaming. We went to the basement locker room and hid there. People were screaming, guests and employees were in panic.

"When we smelled smoke, we decided to go for the exit in the car park. That's where we got out. Before we exited, we heard two gunshots and there was thick smoke on the ground floor."

Eyewitness Hessa Isabelle filmed the scene from a nearby balcony and described seeing "people screaming and running out of the building".

"People are being evacuated out of the building and there's smoke coming out, and they're saying that it's a terrorist attack," she said.

As the situation unfolded, the US state department tweeted a warning to citizens, stating: "Reports of explosions/gunfire at Resorts World Manila, near the Manila Intl Airport. Avoid area & monitor local news."

Ninoy Aquino International Airport, which is around a mile (1.6km) from the resort, was placed on lockdown.

President Donald Trump labelled the incident a terror attack, and offered his "thoughts and prayers" to those affected.

The incident comes as the Philippines army is fighting militants linked to the so-called Islamic State group for control of the city of Marawi on the southern island of Mindanao.