Indian Election Commission took notice after BJP posted images of captured Indian Air Force pilot by Pakistan recently in its election campaign posters.
Pakistan had released the pilot as goodwill gesture.
The Election Commission warned BJP and other political parties to strictly comply with code of conduct.
According to ECI, Polls to elect a new Lok Sabha will be held from 11 April to 19 May. Counting of votes will started on 23 May.
PM Narendra Modi 's ruling BJP will be battling the main opposition Congress and a host of regional parties.
Leaders of two powerful regional rivals have formed a coalition against the BJP in Uttar Pradesh, India's most populous state, and a key bellweather state.
The lower house has 543 elected seats and any party or coalition needs a minimum of 272 MPs to form a government.