They hope to bring together supporters of both Prime Minister Viktor Yanukovych and opposition leader Viktor Yushchenko, one day after the opposition said it was breaking off negotiations and resuming its blockade of government buildings.
In talks on 26 November, the mediators persuaded Yanukovych, the declared winner of the 21 November poll, and Yushchenko to seek to resolve their dispute through talks. The opposition pulled out of those talks yesterday after they failed to make any headway.
Demonstrators have meanwhile surrounded and virtually blockaded the offices of parliament, the government, and the president today.
Opposition supporters stormed into the parliament yesterday shortly after a symbolic no-confidence vote against Yanukovych's cabinet failed to pass.
In an apparent bid to defuse the crisis, Yanukovych yesterday offered Yushchenko the post of prime minister in exchange for both men to be withdrawn from fresh elections, but Yushchenko rejected both options.
Yushchenko claims the 21 November runoff was rigged in Yanukovych's favor, a charge supported by election observers and the West.
Other recent stories include:
"Is Kuchma's Proposal For New Vote A Bid To Sideline Yushchenko?"
"Did President Putin Miscalculate In Ukraine?"
"Ukraine's Parliament Adjourns Without No-Confidence Motion"
"Will Ukraine Split In Wake Of Divisive Ballot?"
[Click here for an archive of RFE/RL coverage of Ukraine's disputed presidential election.]