Police were called to King George's Playing Field in Victoria Road East after the boy reported the terrifying encounter to his parents on Tuesday afternoon (June 28).
The boy’s mother said her son had been riding his bike on the park after school when a group of children unknown to him rushed at him with knives.
The youngster escaped unharmed and peddled home to safety. His mum said the encounter has left him afraid to cycle to school and back by himself.
It follows an incident on Monday evening when another local child was chased by children wielding broken fence posts.
A police spokesman said: “We got a report at 4.46pm on Tuesday (June 28) that a boy had been chased by a group of children, with a knife being seen.
"No assault took place. Officers attended the scene and patrols have been increased in the area.
“An investigation is underway and enquiries are ongoing.”
Police have stepped up patrols around King George's Playing Field since Travellers set up camp last week, in response to incidents of anti-social behaviour.
Wyre Council is also in the process of taking legal steps to remove the Travellers from the park.
A spokesman for Wyre Neighbourhood Policing Team said: “We are aware of the traveller community encampment on King George’s Playing Field, Victoria Road East.
"We understand the community concerns regarding issues such as anti-social behaviour, off road bikes and littering.
"In order to address these issues, a multi-agency led approach is being undertaken to address the concerns and to support the local community.
"We encourage any incident relating to anti-social behaviour and crime to be reported to us via 101 or 999 in an emergency and quote the log number 1070 of June 24.
"Incidents will be investigated thoroughly and deployed to by officers.
"We are also maintaining a high visibility presence in the area as a means of reassurance, this will be undertaken with the assistance of specialist resources across Lancashire.”
A spokesman for Wyre Council added: “We are following the necessary legal procedures to remove the unauthorised encampment in Thornton and have taken measures to secure sites within council ownership.”