Mr Khan said the shooting was "a desperate act by the Congress supporters".
The incident happened post Tuesday midnight outside the AAP office when three rounds were allegedly fired, police said.
The supporters of the AAP and the Congress clashed outside the party office minutes before the firing.
Deputy Commissioner of Police Romil Baaniya said a call was received at 12.10 AM regarding the clash between the workers of the two parties at Batla House Chowk after which the police rushed to the spot.
He said that no one was injured in the firing and both parties blamed each other for it.
"Both parties were asked to give written complaint but no complaint was received from them. Action would be taken as per their complaints," he added.