The pro-Western alliance fell apart in September after lawmakers from the pro-Russian opposition, the Party of Regions and the Communist Party, backed by the Yulia Tymoshenko Bloc, voted to strip the president of his veto on prime ministerial candidates and simplify impeachment procedures.
Parliament overturned on Thursday the laws, which had been denounced by President Viktor Yushchenko as 'anti-constitutional', following demands from the pro-presidential bloc, which set the cancellation of the laws as a condition for forming a new coalition.
Ukrainian Prime Minister Yulia Tymoshenko pledged on Wednesday that her party would accept all of its partners' conditions for forming a new coalition, amid growing fears that the president would dissolve parliament.
After the parliamentary vote on Thursday, Tymoshenko said the pro-presidential bloc must in turn meet its obligations.
However, Vyacheslav Kyrylenko, who heads the pro-presidential Our Ukraine-People's Self-Defense Bloc, said "serious consultations on setting up a new parliamentary coalition" could only resume after the Tymoshenko bloc fulfils further conditions.
If the parties fail to form a coalition, the president can dissolve parliament and call snap elections.
Ex-Soviet Ukraine has been plagued by political instability since 2004. The last parliamentary election took place in September 2007.
