PHNOM PENH (Reuters) - Cambodia on Wednesday banned the game Pokemon Go from a former Khmer Rouge torture center and prison after players showed up at the site, now a genocide museum, hunting for the virtual cartoon characters.

It is the latest effort to rein in enthusiasts of the game, which has been blamed for a rash of accidents and has prompted safety warnings after players glued to their phones stumbled, were robbed or wandered into dangerous places.

"We have guards on standby, any tourists holding iPhones or iPads and playing this game will be asked to leave," Chhay Visoth, director of the Tuol Sleng Genocide Museum, told Reuters. "This is a place of sorrow, not a place to play games."

A handful of Cambodian teenagers was turfed out on Wednesday, he said, adding that the game had been banned in the precincts of the memorial to Cambodia's "Killing Fields" genocide.

Game players use mobile devices to search for virtual Pokemon characters that appear to pop up at office spaces, restaurants, museums and other places where people are known to gather.

In neighboring Thailand, the telecoms regulator announced plans on Tuesday to place certain places, from the Royal Palace grounds and Buddhist temples to hospitals, off limits to players of the augmented reality game.

In the United States, the U.S. Holocaust Museum has asked players to desist, saying playing on its premises is "extremely inappropriate."

A federal class action has even been filed against the companies behind the game, Nintendo Co Ltd , Niantic Inc and Pokemon Company International, by a New Jersey man who says it brought unwanted trespassers to his house and countless other private properties.

At Tuol Sleng, signs warned tourists of the ban, although a Reuters witness spotted no players.

Playing the game at a memorial site was not appropriate, said one visitor to the converted school marking the communist regime's four-year reign of terror that killed at least 1.8 million people.

"There is so much emotion and history here," said French tourist Marianne Kauffmann.

(Reporting by Prak Chan Thul; Editing by Clarence Fernandez)