A cluster of unprovoked late-night attacks on people in Fredericton is under investigation by city police.

The latest of four incidents occurred on Saturday evening, when a 17-year-old male says he and his brother were beaten by 10 males. He told police the group pulled up in two cars as the youths were skateboarding in front of a Price Choppers on the city's north side.

The 17-year-old is in hospital awaiting plastic surgery for broken bones in his face.

The incident occurred just prior to another attack on the south side of Fredericton, where three victims say they had just left a party when they were assaulted by a group of eight or nine travelling in two cars.

A month earlier, on June 11, Scott MacLeod, 27, was jumped by five males on Queen Street. On the same night, local restaurant worker Jason Buchanan was beaten and robbed by six young males.

Deputy chief Leanne Fitch says police are looking for links between the cases.

"At this time, the motive is unknown," she said. "We're looking to see if there is any connection between the suspects involved in those cases."

Police ask anyone with information that may help the investigation to get in touch with them, or call Crime Stoppers.