Staff were evacuated from the Dungannon site of the new Mid Ulster offices after a suspicious package was found in the area on Friday morning.
Police cordoned off the Circular Road and tasked Army Technical Officers to the site.
It’s believed the object was left at the front door of the council building and that graffiti had been daubed on the building.
A controlled explosion was carried on the object which was later described as being ‘nothing untoward’
According to an eyewitness the slogan made reference to the council’s recent ban on the sale of poppies and other poltical emblems at council offices.
Sinn Fein’s Mid Ulster councillor Cathal Mallaghan hit out at those behind the graffiti.
“Unionism attacking our council physically and financially. With spray paint and call-ins. They both hurt the rate payer,” he posted on Twitter.
His party colleague and MP for Fermanagh and south Tyrone, Michelle Gildernew said: “I condemn this attack on the Dungannon Council offices. It is wrong and isnr reflective of the people who live in the Dungannon area.
“The graffiti sprayed on the building read ‘Leave our culture alone’ and ‘Hands off our poppy’.
“The new super council’s decision on the sale of emblems, both the Poppy and Easter Lily, was taken so that council buildings would be a shared space, open and welcome to all.
“Unfortunately there are still those in our society who would wish to counter this progressive policy through actions such as these.
“They will not succeed in deterring the council from its valuable work.”
The MP added: “I would appeal to anyone who saw anything suspicious to bring that information to the PSNI.”