A sixth wave of bomb threats has hit Jewish institutions across the US.

In the latest spate, threats have been made to Jewish community centres in Milwaukee; Rockville, a suburb of Washington DC; Portland, Oregon; Rochester, New York state, Wisconsin and Florida.

In Rochester, about 75 people were evacuated from the building. Parents whose children attend the JCC day care were notified and asked to make alternate child care arrangements for the day.

The threats come after the FBI arrested a man suspected of being behind the threats, Juan Thompson. The Missouri man who appeared in Federal Court on Friday in St Louis.