Army bomb experts have carried out a controlled explosion on a suspect device found at Milltown Cemetery in west Belfast.
Vandals damaged the grave of Gerry Adams' parents
The alert was declared a hoax on Monday afternoon after the device turned out to be a fire extinguisher inside a holdall.
The incident follows a series of attacks on the graves of republicans, including the father of Sinn Fein's Gerry Adams, at the cemetery.
Up to 16 graves were desecrated at the recently refurbished republican plot in Milltown Cemetery in an overnight attack on Monday.
The vandalism was discovered by police who were investigating earlier reports of a suspicious object in the cemetery.
That alert also turned out to be a hoax.
Vandals smashed headstones and scattered flowers laid by the families at the graves, where republicans including hunger striker Bobby Sands and three IRA members killed by the SAS in Gibraltar, are buried.
Sinn Fein councillor Michael Browne said those responsible were "beyond contempt".
Up to 16 graves were vandalised
"This is not simply a republican memorial, it is the actual graves of many IRA volunteers and Sinn Fein activists killed over the past 30 years," he said.
"The monument was recently refurbished through the voluntary work of Belfast republicans."
Mr Adams' father died in November last year.