KIEV Opposition lawmakers surrounded the speaker's rostrum in Ukraine's parliament on Tuesday in protest at what they say is proxy voting by the pro-government majority, stopping the work of the legislature.
Dozens of opposition members, reinvigorated after the ruling party lost seats in an election in October, joined in the protest on the first day of the session after a winter break.
Their success in paralysing the legislature's work shows that President Viktor Yanukovich's allies may have a hard time passing laws ahead of the 2015 election in which he plans to run for a second five-year term.
Any lasting rancour could also prove awkward on Thursday when European Enlargement Commissioner Stefan Fuele addresses the chamber before an EU-Ukraine summit this month that Kiev hopes will lead to the signing of trade agreements shelved over the jailing of former prime minister Yulia Tymoshenko.
Ukraine also hopes to secure a new $15 billion loan package from the International Monetary Fund to help it service foreign debt and cope with an economic slowdown, but talks could take months and could require parliament to pass austerity measures.
The opposition, including deputies loyal to Tymoshenko, nationalists from the far-right Svoboda and a liberal party led by boxing champion Vitaly Klitschko, accuse the ruling coalition of trying to ram through laws despite violating parliamentary rules.
Tymoshenko's Batkivshchyna (Fatherland), Klitschko's liberal UDAR (Punch) and Svoboda (Freedom) have repeatedly accused deputies from Yanukovich's Party of the Regions of voting on behalf of their absent colleagues.
They want to switch from the current system where votes are cast using electronic cards - which can be passed among colleagues - to a system based on fingerprint scanners.
"Every deputy must show up at his workplace and vote in person," Klitschko told reporters.
The Party of the Regions, who together with their traditional communist allies have 240 seats in the 450-member parliament, deny allegations of proxy voting.
Ukraine's parliament is no stranger to high drama. The acrimony between Yanukovich's grouping and the opposition is so deep, that brawls in the chamber are not uncommon.
The anti-Yanukovich coalition formed after the October 2012 election with 177 deputies has actively opposed all major political and procedural moves by the Regions.
In December, deputies wrestled with each other in a mass of bodies around the rostrum as opposition parties tried physically to block a vote on the Regions' candidate for speaker.
After failing to open the new session on Tuesday, speaker Volodymyr Rybak invited opposition leaders for talks about how to unblock parliamentary proceedings.
Tymoshenko's case is likely to remain one of the catalysts of tension in parliament after state prosecutors charged her with a 1996 murder last month.
Tymoshenko, the heroine of protests in 2004 that overturned the old post-Soviet order, is already serving a seven-year jail sentence for abuse-of-office meted out in October 2011 after a trial which the West said smacked of selective justice by the leadership of Yanukovich.
The United States and the European Union have supported Tymoshenko and the EU postponed agreements on free trade and political association with Ukraine over the issue.
The EU and Ukraine are due to hold a summit on February 25 when Kiev wants to resurrect the deals.
(Additional reporting by Natalia Zinets; Writing by Olzhas Auyezov; Editing by Alison Williams)