Travellers have this evening moved from Chester Green and decamped to another area of Derby.
About five caravans and five vehicles were on the site when officer attended the incident.
A spokesman for Derbyshire police said: "We were called to the site at 4.55pm.
"The travellers moved from the site soon after and have now parked up off Newmarket Drive, just off Ascot Drive.
"We will be working alongside Derby City Council to ensure a swift resolution to the situation."
The latest influx to Chester Green came less than a month after travellers moved on to the same site.
Before this, travellers had not been on the green for 15 years.
