A new public service announcement targeted at New Yorkers – on surviving a nuclear attack – has sparked worry and bafflement.

NYC residents are accustomed to warnings about all kinds of potential threats, including severe weather, public health, and mass shootings.

But the 90-second video on nuclear bombs, released this week by the city’s emergency management agency, has led to concern.

Opening on a computer-generated street devoid of life, damaged skyscrapers can be seen in the background.

A narrator says: “So there’s been a nuclear attack. Don’t ask me how or why. Just know that a big one has hit.”

It gives advice to residents, telling them to stay indoors and wash off any radioactive dust or ash.

Christina Farrell, the city’s emergency management deputy commissioner, said the video is not tied to any specific threats.

She said it is about raising awareness of something most people have not given much thought.

“There’s no overarching reason why this is the time we sent this out,” she said.

“It’s just one tool in the toolbox to be prepared in the 21st century.”

Ms Farrell said the agency’s goal is to empower people regarding a scary subject, and despite mixed reactions to the video, “people have thanked us that we are approaching this topic”.

She added: “I don’t know if there’s ever the perfect moment to talk about nuclear preparedness”, saying city officials have discussed implementing nuclear guidelines for quite some time.

New York’s emergency response programme, Ready New York, has been in place since 2003.

Mayor Eric Adams said he does not believe the video is alarmist, telling reporters on Tuesday: “I’m a big believer in better safe than sorry.”