Police have arrested four boys at a South Shore travellers site after windows were smashed at nearby businesses.
Police said they received a call at 6.10am today about criminal damage to buildings on Lockheed Court, South Shore.
A spokesman said: "The building has had its windows smashed overnight.
"We have got another report from yesterday afternoon of people throwing stones at the building."
Glass doors at Hermolle Associates engineering company and Deeper Blue marketing and design were shattered.
A member of staff at Sargent Fitness, also on Lockheed Court, said: "They have smashed the windows in the offices next door. They have tried to force entry to the back of two of the buildings. It looks like they have tried to break their way in."
CCTV shared with The Gazette showed a group of boys hurling stones outside the businesses at around 6.30pm on Sunday.
Police attended a nearby travellers site in connection with the crime this morning. Four boys aged 13, 11, 10 and 10 were arrested on suspicion of criminal damage and are currently in custody.
Six caravans and six vans could be seen on the car park near Lockheed Court, off Amy Johnson Way, this morning. Business owners on the street said they had been there all weekend.
A member of staff at Sargent Fitness said: "It's a complete mess. There's rocks thrown everywhere and rats running around. They have taken rubbish bags and emptied them outside all the businesses. They moved in a few days ago and we have been very nervous."
A member of staff at Hermolle Associates said: "The first I knew was on Friday night. My boss spoke to them and they said they were just there overnight for a party, but they are still there now."
A Blackpool Council spokesman said: "The Council are aware of the presence of travellers on the enterprise zone. The land is privately owned, the owners are fully aware and they are taking appropriate action. Blackpool Council are liaising with them and we will be monitoring the situation closely."