Two cars, over 1000 chairs, canopies and the stage were burnt.
It was gathered that the suspected thugs carried out the act at about 2am.
Sources said shots were fired before the place was set ablaze
The rally was to hold at a field owned by a private individual.
It was learnt that heavy security was being deployed to the area to forestall any attack.
Comrade Oshiomhole was said to have arrived his country home ahead of the rally.