Villavicencio, a former lawmaker and crusading anti-corruption journalist, was gunned down as he left a campaign event on Wednesday, less than two weeks before the Aug. 20 election.

"In the face of the suffering caused by unjustifiable violence, which he condemns unreservedly, His Holiness calls upon all citizens and political forces to unite in a common effort for peace," the Vatican said in a telegram of condolence sent to Archbishop Alfredo José Espinoza Mateus of Quito.

(Writing by Keith Weir; Editing by Andrew Cawthorne)