Opposition leader Viktor Yanukovich secured a lead of slightly more than 10 percentage points over Prime Minister Julia Tymoshenko in the first round of Ukraine's presidential election after all ballots were counted, preliminary results showed on Tuesday.

Yanukovich, leader of the Regions Party, scored 35.32 percent of the vote, while his main challenger Tymoshenko garnered 25.05 percent, according to the Central Election Commission. They will face each other in a run-off on Feb. 7.

The results also showed that 13.06 percent voted in favor of Sergei Tigipko, a former economy minister. His supporters are now crucial in determining the results of the second round.

Fourth place went to former parliament speaker Arseniy Yatsenyuk, with 6.96 percent.

The country's incumbent President Viktor Yushchenko had a total defeat in the first round, winning 5.45 percent of the vote.

The other 13 candidates each won less than 4 percent of the vote.

A total of 2.2 percent of the voters did not vote for any of the 18 candidates. Preliminary data showed turnout was 67 percent.

Sunday's vote was Ukraine's first presidential election since the 2004 Orange Revolution. Over 3,000 international observers monitored the election.

Monitors from the Organization for Security and Cooperation in Europe said the ballot was "of high quality" and showed significant progress on previous elections.

Yanukovich, who draws the bulk of his support from the Russian- speaking areas of the industrial east and the south, has promised Ukrainians economic revival, new jobs, pay raises, judicial reforms and tax-free policies for small enterprises for five years.

Tymoshenko, an ally of Yushchenko in the Orange Revolution, gave priority to a fair society and government efficiency, and pledged an innovation-driven economic structure reform and improvement in people's welfare. Her powerbase is in the west of the country.

Both leading candidates have pledged to mend ties with neighboring energy supplier Russia.