Ukraine's opposition held direct talks with President Viktor Yanukovych Friday for the first time in more than three weeks of mass anti-government protests.
But opposition leaders emerged from the meeting, which included other political and civil society respresentatives, saying the president failed to meet their demands.
Among other things, the head of the Udar, or "Punch," party -- Vitaly Klitschko -- and Ukraine's other main opposition leaders are calling for the release of jailed protesters.
The Ukrainian president has proposed amnesty for those arrested in the protests. But that was not enough for the opposition, which called for Mr. Yanukovych and his government to step down.
The demonstrations erupted after the Ukrainian leader decided not to sign a long-awaited European Union trade pact in order to avoid losing trade with Russia. Ukrainian police responded with a crackdown.
The opposition has called for a new mass protest on Sunday. Supporters of Mr. Yanukovych are also planning a rally.
As the tensions continue, the United Nations human rights agency Friday called on all parties involved to "exercise restraint."
A spokeswoman for the U.N. High Commissioner for Human Rights said the agency is following the events in the Ukrainian capital, Kyiv, closely and warns against "the risk of further escalation, violence and polarization." She said the agency is particularly concerned about reports of riot police using "excessive force" and violent acts by some demonstrators.
On Thursday, a key European Union envoy said the 28-member trade bloc is ready to provide more financial aid to Ukraine, if Kyiv agrees to sign the trade cooperation agreement it backed away from last month. EU foreign policy chief Catherine Ashton said this week Mr. Yanukovych "intends to sign" the trade pact.
Kyiv is reportedly in need of more than $20 billion to meet immediate foreign obligations, including natural gas payments to Moscow.
Russia is seeking to form a trade bloc of former Soviet republics and satellite countries to rival the European Union, and has in recent months exerted strong economic pressure on its impoverished neighbor to scuttle the EU deal.