International election monitors have hailed Ukraine's presidential elections as "professional, transparent and honest.

The Organization for Security and Cooperation in Europe's glowing assessment Monday is likely to increase pressure on apparent loser Yulia Tymoshenko to concede the election.

Joao Soares, head of the observation mission from the OSCE's Parliamentary Assembly, said Sunday's vote was an impressive display of democratic elections.

Opposition leader Viktor Yanukovych was the apparent winner, with a 2.6 percent lead and less than 2 percent of ballots remaining to be counted Monday.

Tymoshenko has alleged fraud and manipulation and signaled she will challenge the outcome in the courts. She is due to make a statement Monday afternoon.