The European Union delivered formal congratulations to Ukraine's novice president-elect Monday but made clear it expects TV comic Volodymyr Zelenskiy to pursue halting reforms, including fighting corruption.

In a joint letter as Zelenskiy's landslide victory over President Petro Poroshenko was confirmed, European Council President Donald Tusk and European Commission President Jean-Claude Juncker praised the conduct of the election even though parts of Ukraine remain under the control of pro-Russian forces.

But they stressed that five years after Poroshenko was elected in the wake of a popular revolt against a Moscow-aligned predecessor, Ukraine still has a long way to go to deliver on people's demands for peace, democracy and prosperity.