Workers say they were left terrified when a group of travellers broke onto a Preston business park and threatened them with violence.
Security staff called the owners of Broughton Business Park on Caxton Road, Fulwood, to say around 11 caravans had parked behind the building after breaking down the gates on Saturday evening.
Staff arrived at around 7.40pm worried that expensive machinery could be damaged by the group.
One of the workers, who asked not to be named, said: “When we arrived we wanted to move our machines because they’re worth hundreds of thousands of pounds.
“When we tried to go over we received death threats and knives held to our throats.
“There were children hitting us with golf clubs and one guy in a balaclava was walking around with a machete.
“We called the police who helped us move the machines but then they left and we had to fend for ourselves while we tried to get them to leave.”
The owners allege the group of “20-25 travellers” also damaged the power supply at the site leaving it without electricity until yesterday afternoon.
The site, which used to be home to Broughton Printers and the Lancashire Evening Post, is in the middle of being cleared out before it goes back up for rent.
One of the men at the scene said: “The abuse we received was disgusting and we really did fear for our lives.”
A spokesman for Lancashire Constabulary said there were no reports of any injuries during the incident.
The spokesman said: “We were called during the evening of Saturday, July 1 to reports that travellers were on the site of Broughton Printers on Caxton Road.
“We attended and spoke to both parties. The travellers have since left the site.”