Armed police swooped on Witham Way Country Park in Boston this morning after reports of a firearms incident.
Witnesses reported seeing two teenagers firing what appeared to be an air rifle or pellet gun at about 10.55am.
A large-scale armed police response at the site was followed by a search of the area, but nothing was found.
A police spokesman said: “It seems there were a couple of teenagers with an air rifle who ran away before police got there.”
They added: “Whenever there’s a mention of someone using a firearm, it’s standard practice we respond as though it is a firearm incident.”
It is not known what they were allegedly firing at.
Anyone with information about the incident can contact Boston Police by dialling 101 and quoting incident number 114 of today (February 6) or call Crimestoppers anonymously on 0800 555111.