The legend has it that Shivaji had a loyal dog called `Waghya', who jumped into his master's funeral pyre and killed himself.
But the activists wanted the statue removed, saying that the legend had no historical basis.
The act led to tension on the historical fort, where Shivaji breathed his last in 1680, but there was no further trouble, the police sources said.
Over ninety people were detained by police, but FIR was yet to be registered.
The police and locals later retrieved the dog's statue, and it was being reinstalled, they added.
Sambhaji Brigade, a Maratha group, was responsible for vandalising of Bhandarkar Oriental Research Institute at Pune in 2004.
The Fort falls under the jurisdiction of Archaeological Survey of India.