Ukrainian Prime Minister Yulia Tymoshenko...

With 97.84% of the ballots counted from the runoff vote, opposition leader Viktor Yanukovych leads with 48.5%. Tymoshenko, who before the polls accused her opponent of trying to rig the election, has 45.91%.

Tymoshenko"s willingness to challenge the results of the vote is seen as pivotal to political stability in the former Soviet state.

The news conference was initially planned for 14:00 Moscow time (11:00 GMT), but was later postponed until 18:00 Moscow time (15:00 GMT) before being put off until Tuesday.

The government press service said the time would be announced later.

KIEV, February 8 (RIA Novosti)