Ukrainians voted Sunday in an election that is likely to install a pro-Western parliament and strengthen President Petro Poroshenko's mandate to end separatist conflict in the east, but may fuel tension with Russia.

Voting started on a cold but sunny morning in Kiev in the first parliamentary election since street protests in the capital last winter forced Moscow-backed President Viktor Yanukovych to flee and ushered in a pro-Europe leadership under Poroshenko.

A loose political grouping that backs Poroshenko is expected to become the leading force in the 450-seat assembly, giving him a mandate to pursue a peace plan for the east and carry out deep reforms sought by Ukraine's European Union partners.