KIEV, Aug. 7 - President Viktor Yushchenko on Tuesday praised the newfound unity of backers of the ''Orange Revolution'' that swept him to power in Ukraine and demanded a new drive for victory in next month's parliamentary election.

The pro-Western Yushchenko defeated arch-rival Viktor Yanukovych in the re-run of a rigged 2004 presidential election after weeks of mass ''orange'' protests in his favor.

But infighting led to the collapse of his first government, allowing Yanukovych to win back his job of prime minister and unleashing a power struggle between the two men.

Polls suggest the election will change little in Parliament.

Liberal chances have been boosted by an alliance between the president's Our Ukraine party and a new grouping. But fiery ex-premier Yulia Tymoshenko, aligned with the president after a period of estrangement, is to field candidates separately.

Yushchenko told a party congress the bickering was over.

''The battle of the medieval chiefs has ended. This is what all the Ukrainian people have been waiting for,'' Yushchenko said, Reuters reported.

Tymoshenko's bloc is ''advancing alongside us, shoulder to shoulder,'' he said. ''Our common victory depends on how we help each other and how we coordinate our work.'' Yushchenko's 2004 victory over Yanukovych and Ukraine's longstanding political establishment spawned ambitious hopes among liberals that Ukraine could one day join major Western institutions, including the European Union and NATO.

But infighting disillusioned many Ukrainians who had hoped for a definitive break with the Soviet past. Yanukovych’s Regions Party came first in last year's parliamentary election and formed a ruling coalition with Socialists and Communists.

Yanukovych has hinted that he and Yushchenko could forge a ''grand coalition'' of their parties after the Sept. 30 poll, but the president has refused publicly to consider this.

Tymoshenko, dismissed as Yushchenko's prime minister in 2005 after eight months in office, opened her campaign at the weekend addressing supporters in her trademark peasant braid and a stylish Ukrainian national costume.

Yanukovych, backed by the Kremlin in 2004, has toned down calls for closer ties with Russia. Foreign policy rarely figures in debate, both sides promising to build on economic growth forecast at 6.5% this year and raise living standards.

The election was prompted by the president's dissolution of Parliament on grounds that the prime minister was illegally trying to boost his majority in Parliament to change the constitution and further reduce Yushchenko's powers.

Surveys put Yanukovych’s Regions Party in the lead with 30% or more, with a further five per cent for its communist allies. Yushchenko's Our Ukraine, allied with the Self-Defense group, has 15% or more, as does Tymoshenko's bloc. (rs/ez)