Authorities in northern Colorado are looking for leads after a 20-year-old woman says she was shot in the neck while she drove on Interstate 25.

Larimer County Sheriff's Office spokesman David Moore says the woman was driving along open fields near Windsor on Wednesday night when her windshield shattered, and she realized she had been shot.

She was able to pull over safely and call for help. The woman was taken to a hospital and underwent surgery, but it's not known how she was doing Thursday.

The shooting came two days after a sheriff's van transporting prisoners was hit by some kind of projectile on I-25, shattering a passenger window.

The two incidents on Colorado's main north-south highway happened about 20 miles apart. Moore says it's too soon to say whether they could be related.