KIEV, March 29 - Ukraine's presidential election effectively became a two-horse race on Saturday after boxer-turned-politician Vitaliy Klitschko pulled out and threw his weight behind confectionary oligarch Petro Poroshenko, Reuters reported.

Klitschko's withdrawal sets up a May 25 contest between the man known as the 'Chocolate King' and former prime minister, Yulia Tymoshenko.