Ukrainian PM Arseniy Yatsenyuk speaks in the parliament in Kiev on July 24. (Associated Press)
The pro-Russian party that ruled Ukraine under ousted president Viktor Yanukovych said Sunday it would boycott next month's parliamentary polls and form an "opposition government" to fight for regional powers and against Kiev's westward course.
The decision by the once-dominant Regions Party came as top politicians formed leadership lists for the October 26 election that was called early to regain people's trust after two decades of post-Soviet corruption and economic malaise.
The polls have been an afterthought for many horrified Ukrainians watching their nation being ravaged by a pro-Russian eastern uprising that erupted in the wake of the toppling of the Kremlin-backed Yanukovych in February.
But the new 450-seat chamber will enjoy additional powers that could make its cooperation essential to President Petro Poroshenko's attempts to pull Ukraine out of its worst security and economic crises since independence in 1991.
The Verkhovna Rada parliament will nominate prime ministers and have the right to sack top cabinet members without prior consultation with the president.
A new People's Front created by Prime Minister Arseniy Yatsenyuk and the president's own Petro Poroshenko's Bloc are expected to form the bedrock of the current leadership's parliamentary support.
But the Regions Party - winner of the last election in December 2012 and long viewed as the domain of powerful tycoons with strong Russian connections - pulled out of the race before it even began.
The party said in a statement it was forming an opposition government that will fight for "a real decentralisation of power - in other words, awarding each region control over its own budgets".
- Wartime election -
Regions Party leader Borys Kolesnykov expressed exasperation at the idea of an election being held "when there is a war (and) when people are dying".
The group had relied on the support of the Russian-speaking eastern regions of Lugansk and Donetsk - hotbeds of the current uprising where pro-Moscow rebels have declared their own "people's republics".
Poroshenko hopes that a September 5 ceasefire will calm tensions enough to let the two regions vote and enable his government to demonstrate the progress made in the first months of his rocky term.
The election will offer the public the first chance to pass judgement on the 48-year-old tycoon's ability to steer the country closer to the West while avoiding Russian retaliation, which could entail a direct invasion or a possible economic blockade.
The president's somewhat unimaginatively monikered Petro Poroshenko Bloc will be headed by former heavyweight boxing champ and new Kiev mayor Vitali Klitschko - arguably Ukraine's biggest sporting hero and most appealing member of a widely despised political establishment.
"We have to win as many seats as possible so that there is little space left for forces who are trying to destroy Ukraine," Klitschko told a party congress.
Yatsenyuk will head a new People's Front that also includes Interior Minister Arsen Avakov - a hate figure in the Kremlin - as well as parliament speaker and brief interim president Olksandr Turchynov.
But former pro-Western prime minister Yulia Tymoshenko decided not to head her own Batkivshchyna (Fatherland) party after sticky corruption allegations saw her collect a humbling 13 percent in the May presidential election.
The former opposition star who was jailed under Yanukovych's government will run in the number two slot behind the enigmatic Nadiya Savchenko - Ukraine's only female aviator of a Su-24 bomber who is currently sitting in a Russian jail.
The 33-year-old Savchenko fought as a volunteer against the insurgents before being captured in June.
She has been charged over the deaths of two Russian television reporters who pro-Kremlin media say were deliberately shot by Ukrainian troops.