Days after the release of Nintendo's smartphone game, "Pokémon Go," the US Holocaust Memorial Museum in Washington is trying to have the landmark removed from the app.

The communications director at the US Holocaust Memorial Museum, Andrew Hollinger, said playing the game inside a memorial to victims of Nazism is "extremely inappropriate."

Like many other landmarks, the Holocaust Memorial Museum features in the popular new game "Pokémon Go" as a so-called "Pokestop," where users can collect free in-game items.

Players can stumble upon Pokémon while wandering the grounds using their phone's camera to track down the virtual creatures called Pokémon - long confined to the realm of video games and television shows - which pop up on screen as if there in reality. As Pokémon "trainers," users try to catch them and ready them for battle.

'Inappropriate'

Arlington National Cemetery in Virginia has also called for a similar ban on the game. Spokesman Stephen Smith said the move was pre-emptive rather than to address a problem they're already experiencing.

"Playing games such as 'Pokémon Go' on these hallowed grounds would not be deemed appropriate," Smith said, adding that the cemetery's layout makes it difficult to know whether a visitor is playing the game on their phone or using the cemetery's own app to navigate landmarks.

In a tweet on Tuesday, the Auschwitz memorial in Poland wrote: "Do not allow playing #PokemonGO on the site of our Mermorial and similar places. It's disrespectful on many levels."

Overnight success

Following the launch of "Pokémon Go" in the US, Australia and New Zealand last week, slumping Japanese video game developer Nintendo was transformed into an overnight celebrity on the app market.

Experts believe that in the first day alone, one in 20 US owners of Android cell phones downloaded the free app, which also soared to the top of Apple's iTunes list of most-popular app downloads.