A police officer is among five dead after a gunman opened fire in broad daylight in the centre of New York City.
The assailant, who has been pictured holding an assault rifle, began shooting inside a glitzy Manhattan skyscraper that is home to the Irish consulate and firms including Blackstone and the NFL.
The shooter, who went on to kill himself, was revealed to be 27-year-old Shane Tamura from Las Vegas.
Legions of emergency vehicles rushed to the skyscraper at 345 Park Avenue after his attack.
The police officer killed, named locally as Didarul Islam, who was working private security at the time, was said to have been shot in the back.
The NYPD later paid tribute to the fallen policeman, saying in a tribute how he "represented the very best of our department".
"He was protecting New Yorkers from danger when his life was tragically cut short today," police said. "We join in prayer during this time of incomprehensible pain. We will forever honour his legacy."
PICTURED: A man 'wanted in connection with the shooting'
|NYPD
PICTURED: Police officers gather during a reported active shooter situation in the Manhattan borough of New York City
|REUTERS
"An incident has occurred outside of the building," said a warning broadcast on the fifth floor of a nearby block on 399 Park Avenue at the time.
"Please stay inside, shelter in place, stay away from the windows until further instructions from the NYPD," the person issuing the alert says over the system.
A witness told NBC News: "I had a bit of a PTSD response that came out of the blue... I lived through 9/11 and all the sights and sounds reminded me of that day. I'm ok now."
New York Congressman Ritchie Torres branded the attack a "shocking act of terror" and said the gunman had left three people "critically injured".
LATEST FROM NEW YORK:
PICTURED: Ambulances queue up near the scene after the 'mass shooting'
|REUTERS
"We must all pray for the full recovery of those who have been injured," he said.
The FBI also descended on the scene - with the Bureau's Deputy Director Dan Bongino confirming agents were in place.
NYC Mayor Eric Adams, meanwhile, ordered locals to not go outside in the local area.
"New Yorkers: there is an active shooter investigation taking place in Midtown right now," Adams said.
"Please take proper safety precautions if you are in vicinity and do not go outside if you are near Park Avenue and East 51st Street."
PICTURED: FBI agents investigate near a New York Police Department response vehicle near the scene
|REUTERS
"At this time, the scene has been contained and the lone shooter has been neutralised," NYPD Commissioner Jessica S Tisch said.
Tamura died of a self-inflicted gunshot wound, four senior New York City officials said.
Preliminary checks did not show a "significant criminal background", officials told CNN.
It remains unclear whether he had a specific target - or why he was at the building.
More From GB News