At least five people were shot at a splash pad in Rochester Hills, Michigan, in what the local police described as “an active shooter situation”, according to the Detroit News.

The shooting occurred about 5pm at the Brooklands Plaza splash pad, where children sometimes play while cooling off in the summer. Police had no details about the victims, their ages or their conditions, and a spokesperson told the Detroit News that at least one additional person may have been shot.

Police also said the whereabouts of the shooter were unclear. No other details were immediately available.

The term “active shooter” is usually associated with mass shootings.

In the US as of Saturday, there had been more than 215 mass shootings so far this year, according to the Gun Violence Archive.

The nonpartisan online resource defines a mass shooting as one in which four or more victims are wounded or killed.

Such a high rate of mass shootings in the US has prompted calls to Congress for lawmakers to pass more substantial gun-control measures, but such requests have largely gone unheeded.