The dismissal of Susanna Stanyk came after the sacking of Valeriy Pshenychny, Constitutional Court deputy chairman, on similar grounds Monday, while the court is examining the legality of the president's initial, April 2, order to disband parliament and call early elections, challenged by the legislature.
Ukraine's majority coalition in parliament said earlier Tuesday Pshenychny's dismissal was illegal.
"This step taken by the president is designed to block the work of the Constitutional Court, the only body capable of bringing relationships between the branches of power in line with law," the coalition's largest Party of Regions said in a statement.
The party led by Prime Minister Viktor Yanukovych, Yushchenko's long-time rival, said lawmakers would again refer the case to the Constitutional Court.
On April 26, Yushchenko issued another decree to postpone early elections from May 27 to June 24 over the government's reluctance to allocate funds. That order was also taken to the Constitutional Court, which has not made a decision yet.
On Monday, the Supreme Rada voted to hold presidential elections along with parliamentary polls. The decision was backed by 234 lawmakers, with 226 votes being required for it to be passed. The legislature said polls should take place within 90 days after relevant changes were made to the Constitution, but no later than December 9, 2007.
But at least 300 votes are needed to amend the Constitution, whereas only 254 lawmakers are working in the Supreme Rada at the moment after pro-presidential factions quit the disbanded parliament.
Ukraine's current political crisis broke out after Yushchenko first disbanded parliament April 2, accusing Yanukovych of enticing 11 pro-presidential lawmakers to join the majority coalition controlled by his party since he came to power as premier after the March 2006 parliamentary elections.