A series of reckless incidents involving dirt bikes, ATVs and bicycles caused disruptions and safety concerns Sunday evening in Middlesex, police say.

The Middlesex Borough Police Department reported multiple encounters with groups of riders who ignored traffic laws and deliberately refused to comply with officers’ orders.

The first incident happened around 6 p.m. when a group of dirt bikes and ATVs was seen riding erratically along Route 28.

Police say riders were performing stunts in traffic and failed to stop when officers attempted to intervene. Later that evening, around 8:15 p.m., police say a separate group of bicyclists engaged in similar behavior.

Authorities tracked the group along Route 28, through the Middlesex Shopping Center and onto the grounds of Von E. Mauger Middle School.“This behavior is not only illegal, it puts lives at risk,” the department said in a statement, adding that residents, pedestrians and the riders themselves were endangered.

Police say they are reviewing all available evidence to identify those involved.

Officials say anyone found to have participated will be held accountable to the fullest extent of the law.