Ukraine's opposition pressed for the resignation of President Viktor Yanukovich on Saturday in the wake of a deal to end days of carnage in the capital.
Thousands of protesters on Kiev's Independence Square are demanding Yanukovich go immediately, sceptical of a European Union-brokered accord under which the embattled leader agreed to give up powers, hold early elections by the end of the year and form a government of national unity.
The UDAR (Punch) opposition party of Vitaly Klitschko said it would submit a parliamentary resolution calling on Yanukovich to quit to clear the way for early elections.
"We will submit the resolution with the demand for Yanukovich to resign," party spokeswoman Oksana Zinoviyeva told Reuters. "It will allow the parliament to set the date for early elections."
Addressing the crowd on Independence Square, Klitschko said he would seek support from lawmakers "to get rid of" Yanukovich. Protesters cheered and chanted "Bandits out!"
Yanukovich was due to visit the northeastern city of Kharkiv on Saturday, but it was not clear whether he had arrived.
The EU-brokered deal followed two days of violence that turned central Kiev into a war zone and left 77 people dead.
The protesters are refusing to leave the square, demanding Yanukovich step down.
"I believe parliament today will be dissolved and Yanukovich will be ousted," said 58-year-old protester Vasyl Lubarets.
As the parliament sitting opened, the speaker of the assembly, Volodymyr Rybak, said he was standing down due to ill-health.