What to Know The augmented reality game became the top grossing app in the iPhone app store just days after its Wednesday release

Gamers are so engrossed in the app that it potentially puts them at risk, some law enforcement officials say

Users say they're not concerned about potential hazards, and that the game helps them exercise

The subway rider with his or her head buried in an iPhone may be tossing "Pokeballs" on their screen in a virtual game of "Pokemon Go," an augmented reality game that has stormed the country -- and prompted warnings from officials about the real-life dangers of keeping one's head buried in a screen.

The augmented reality game, which layers gameplay onto the physical world, became the top grossing app in the iPhone app store just days after its Wednesday release in the United States, Australia and New Zealand.

Images of the Pokemon on MTA buses and trains have since littered Instagram and other social media, prompting the NYPD to tweet a warning about playing while driving that, of course, features a rare get in the game.

Yeah we know Charizard is rare but don't let Officer Monello & his new partner catch you! Don't #CatchEmAll & drive! pic.twitter.com/S0ipjYTDeY — NYPD 19th Precinct (@NYPD19Pct) July 11, 2016

Last week, a 21-year-old communications graduate on Long Island was so engrossed in the app he fell on his skateboard while cruising for critters.

He cut his hand on the sidewalk after hitting a big crack, and blames himself for going too slowly.

"I just wanted to be able to stop quickly if there were any Pokemons nearby to catch," he says. "I don't think the company is really at fault."

In Missouri, gamers so engrossed in the app were targeted by armed robbers, according to NBC News. And in Wyoming, a 19-year-old woman in Wyoming went out to find a "water-type Pokemon" and encountered a dead body.

A two-hour security lockdown disrupted thousands of travelers at Detroit Metropolitan Airport late Thursday after a passenger entered a secure zone without submitting to a security check, NBC News reported.<a href="http://www.nbcnews.com/news/us-news/detroit-airport-security-lockdown-snarls-thousands-n118201" class="linkout" target="_blank"> Read More</a>

The Pokemon Company International did not immediately return NBC News' requests for comment, but many New Yorkers said they were not concerned about the potential hazards. They said the game helps them exercise.

To play, you fire up the game and then start trekking to prominent local landmarks — represented in the game as "Poke stops" — where you can gather supplies such as Pokeballs. Those are what you fling at online "pocket monsters," or Pokemon, to capture them for training. At other locations called "gyms" — which may or may not be actual gyms in the real world — Pokemon battle one another for supremacy.

As players move around the real world, their phones vibrate to alert them when virtual Pokemon are nearby, according to the game's website. Players can then flick a thumb on their screens to throw a Pokeball at the pocket monsters to capture them. The game also allows players to take a photo of the creatures as they appear on the screen.

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