KIEV, August 2 (RIA Novosti) - An election campaign officially starts in Ukraine Thursday, 60 days before parliamentary polls fixed ahead of schedule in a bid to end a bitter political crisis in the ex-Soviet state.

The early elections were set June 4 as part of a deal between President Viktor Yushchenko and his arch-rival Prime Minister Viktor Yanukovych amid a crisis that broke out after the president accused in early April the premier-controlled majority coalition of usurping power and ordered the legislature to dissolve.

Experts say the configuration of political forces in the run-up to the new elections has not changed significantly since the March 2006 polls, with the same five or six parties and blocs likely to make it into the Supreme Rada after September 30.

Opinion surveys show that Yanukovych's Party of Regions is still in the lead with approval ratings ranging from 28.5% to 30.2%. Pro-presidential Our Ukraine bloc comes next, enjoying the approval of 14.3%-17.6% of respondents in the latest surveys.

The bloc led by Yulia Tymoshenko, Yushchenko's fiery ally in the 2004 "orange revolution" protests that swept him to power and in opposition to the premier in the latest standoff, is the third most popular group with 11.6%-14.3%. And the Communists, members of the majority coalition in the previous parliament, enjoy the approval of 3.2%-5% of respondents in various surveys.

Experts say the other member of the coalition, the Socialist Party, could also overcome the 3% threshold, with its approval ratings varying from 1.1% to 4.8%.

Ukraine has been rocked by a power struggle between the pro-presidential factions seeking integration into the EU and NATO, and the more Russia-friendly Yanukovych, who was defeated by Yushchenko in the 2004 presidential race, but returned to politics last year after his party won a majority of the seats in parliament and formed the ruling coalition.