Suffolk Count Police say it happened at 8:50 p.m. Tuesday near a baseball field close to the annual Huntington Manor Fire Department Firemen's Fair at Stimson Middle School on Oakwood Road.
Suffolk County Police say a group of teens and young men started fighting.
A 14-year-old boy was stabbed and seriously injured.
A 17-year-old boy suffered stab wounds described as non-life-threatening.
The 14-year-old victim's cousin told Eyewitness News that he's expected to be OK, and was not sure who was fighting.
It's not clear if the two teens were ever at the fair before the stabbing, or what, if any, their relationship was to each other.
"I'm in shock. It's honestly like... never say never because I went to this fair last year and I didn't hear any incidents, but usually the years before there were many incidents," said middle school student Emily St. Rose.
As of Wednesday morning there had been no arrests.
Police plan to step up patrols at the fair, which continues through Saturday.
They are searching for the motive, a weapon and surveillance video.
"Cell phone videos, videos from the school district, videos from the surrounding neighborhoods that may show suspicious activity, before, during and after the fight," said Suffolk County Police Department Chief of Detectives William Doherty.
Detectives are asking anyone with information on Tuesday's incident to contact the Second Squad at 631-854-8252 or Crime Stoppers at 800-220-TIPS.
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