Suspected thugs on Saturday disrupted an African Democratic Congress (ADC) event in Kaduna, leaving several supporters injured and property vandalised.
Viral videos circulating online show the attackers storming the venue, which was decorated in ADC colours, and assaulting participants.
Photos from the scene also revealed party members with varying degrees of injuries.
The incident comes weeks after opposition politicians formally adopted the ADC as the platform for a united front against the ruling party.
Among key figures in the coalition is former Kaduna State governor, Nasir El-Rufai.