Viktor Yushchenko's initiative came amid a power struggle between the "orange" opposition and the ruling coalition in parliament, which escalated further after 11 opposition members joined the ruling coalition led by Yushchenko's arch rival, Prime Minister Viktor Yanukovych, March 23.
"The head of state wants the prime minister and the government coalition to ensure the inviolability of constitutional provisions in forming the parliamentary coalition," Yushchenko's press service said.
The president, who came to power on the back of the "orange revolution" in 2004, demanded Friday that he and the prime minister draft a joint address to the Constitutional Court to hold lawmakers responsible for defections, the presidential press service said.
Yushchenko was expected to meet with senior members of the Supreme Rada and leaders of political factions Friday, but the consultations were postponed.
Opposition parties have said they would hold protests in Kiev's central square, Maidan, Saturday to demand the dissolution of parliament and early elections.
"Protests by the united opposition, including Our Ukraine, the Yulia Tymoshenko Bloc and the People's Self-Defense party, will be held in the square at 5 p.m. [2 p.m. GMT] Saturday," an Our Ukraine representative said.
The president has not ruled out the possibility of early elections, and his secretariat has already prepared a draft decree that tentatively schedules polls for May 27. But the Supreme Rada will first have to obtain permission from the Constitutional Court to dissolve parliament.
Parliamentary elections in Ukraine in March 2006 saw the Party of Regions come first, followed by the Tymoshenko Bloc and Our Ukraine. The Party of Regions, the Socialists and the Communists formed a majority coalition after five months of political wrangling, and elected Yanukovych prime minister in August.
The power struggle between the prime minister and the president broke out after the country was transformed from a presidential into a parliamentary republic by constitutional amendments following the "orange revolution."
