SWANZEY, N.H. — New Hampshire officials are investigating an all-terrain vehicle crash that seriously injured two teenagers.

The New Hampshire Fish and Game Department says the 14-year-old operator and a 14-year-old passenger were hurt while riding on Taylor Hill Road in Swanzey at 6:20 p.m. Saturday.

The teenagers were taken by ambulance to Cheshire Medical Center in Keene.

Investigators say speed and inexperience were contributing factors in the crash.

Officials say it it’s illegal to operate ATVs on public roads and that riders must have a valid driver’s license or have completed a safety course. It’s also illegal for an operator under 18 to carry a passenger on an ATV.