About 20 opposition lawmakers have spent the night in the Ukrainian parliament chamber after blockading it in a voting dispute.
Deputies from the opposition Udar (Punch) party, led by world heavyweight boxing champion Vitaly Klitschko, spent the night from Tuesday to Wednesday in the parliament chamber.
The dispute in Ukraine's one-chamber parliament, known as the Verkhovna Rada, centres on opposition demands for each deputy to vote individually.
Voting in the Ukrainian legislature is done electronically and lawmakers can delegate the right to vote to their colleagues.
The chamber is the scene of frequent brawls, with burly deputies sometimes resorting to physical violence during debates.
Along with deputies from two other opposition parties, the Batkivshchyna alliance and nationalist Svoboda, Udar members have vowed to continue blocking the parliament until pro-government deputies meet their demands.
Klitschko himself has at times joined the blockade, where protesting deputies are wearing red, long-sleeved T-shirts emblazoned with the slogan: "Vote Yourself!"
"According to the constitution, each deputy must come to work ... and vote individually," Klitschko said in videotaped comments posted on his party's website on Wednesday.
He warned that pro-government lawmakers could resort to the use of force to get into the chamber.
The opposition and critical media have repeatedly accused pro-government deputies of frequently missing parliamentary sessions and asking colleagues to vote on their behalf.