KIEV -- Ukrainian electors, preferring sunshine to voting for the fifth time in four months, stayed away in droves from polling stations in more than 100 weekend by-elections, preliminary results showed Monday.


Election officials said only about 20 challengers won outright in Sunday's voting for 112 seats left open after a general election in April -- almost a quarter of the 450-seat chamber.


Parliamentary by-elections where turnout did exceed the required 50 percent and gave an outright majority produced a smattering of centrists, likely to support President Leonid Kuchma in a power struggle with the leftist chamber.


"For the most part these are ... not Communists. I'm convinced they will join the centrist factions, not the left-wing," said Ihor Tseluyko, secretary of the Central Election Commission.


A second round of voting in 45 districts will take place in two weeks. Voting was declared invalid in 47 districts, where turnout was under the limit -- hardly surprising at the height of the summer holiday season.


Kuchma, who won a decisive victory two weeks ago over outgoing Leonid Kravchuk, has only a small base of support in the assembly. His own Inter-regional Reform Bloc has only 27 seats in parliament.


His calls for a stronger presidency could be threatened if Communists and their allies win enough seats to form a constitutional majority of 300 deputies.


Kuchma also says he intends to create a unified system of executive power "from the top down" -- plans which are sure to be opposed by the parliament.


But the outcome appeared to buck a trend set in the general elections, when Communists scored high in the industrialized, Russian-speaking eastern part of Ukraine.


Among those who passed the first round were former Nationalities Minister Olexander Yemets, Deputy Interior Minister Valentyn Nedrehaylo, and Deputy Foreign Economic Relations Minister Volodymyr Hladush.


Others included factory bosses and local political personalities, not avowed Communists, Tseluyko said.


Leftist factions, under the leadership of Socialist parliament chairman Olexander Moroz, favor weakening the presidential post or wiping it out altogether.


Under the current, Soviet-era constitution, Kuchma is head of the executive branch as well as head of state. But the post is far weaker than that of Russian President Boris Yeltsin.


Kuchma is betting on centrist support for his pledge to implement "evolutionary" reforms and end more than two years of economic collapse which he says has put 90 percent of Ukraine's 52 million people below the poverty line.


Speaking to reporters outside a central Kiev polling station Sunday, Kuchma defended the first action he undertook after his inauguration -- a crackdown on crime.


"Ordinary people back this decree," he said. "The only people opposed to it are the fat cats."


He added he would move forward to clinch a friendship treaty with Russia, still unsigned more than two years after the collapse of the Soviet Union. Such a treaty, he said "does not mean a return to relations of the Soviet era."


Western nations will be watching Ukraine's reform plans carefully as $4 billion in aid pledged at the recent Group of Seven leading industrialized nations summit is contingent on concrete reforms.


Four governments under Kravchuk's stewardship failed to produce a comprehensive reform program.