Ukrainian election officials said a record 44 candidates have registered to run in the March presidential election.
President Petro Poroshenko is seeking a second five-year term and has vowed to press for European Union and NATO membership for the country.
Recent polls indicate former Prime Minister Yulia Tymoshenko and comedian Volodymyr Zelensky will be Poroshenko's closest rivals in the March 31 election.
The 53-year-old Poroshenko, one of Ukraines richest men, came to power in the aftermath of the pro-European Maidan protests that pushed Moscow-friendly President Viktor Yanukovych out in February 2014.
He has vocally advocated closer integration with the West and criticized Russia following Moscow's seizure of Ukraines Crimea region and amid a continuing war against Russia-backed separatists in the eastern region known as the Donbas.
Tymoshenko, 58, was a leader of the 2004 Orange Revolution but was defeated by Poroshenko in the 2014 presidential election.
Former Deputy Prime Minister Yuriy Boyko is also among those who registered.
Based on reporting by AP and AFP
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