Khawaja Izharul Hasan escaped uninjured in the attack on Saturday after Eid prayers, in the southern port city of Karachi.
Police officer Pir Mohammad Shah said one of the attackers was also gunned down by police during a chase, AP reported.
Mr. Hasan belongs to the Muttahida Qaumi Movement, which represents the Urdu speaking population.
He was meeting and greeting people after Eid prayers when gunmen struck in a north Karachi neighborhood.
The party was divided after its self-exiled founder, Altaf Hussain, uttered anti-Pakistan remarks in London last year. He is wanted in many criminal cases back home.