KIEV, June 7 - Three pro-Western parties, which control a simple majority in Parliament, voted Wednesday to postpone sessions for a week after an ultimatum from one of the parties had nearly undermined a coalition agreement.

The Socialist Party suddenly refused to back the agreement Wednesday morning unless its leader, Oleksandr Moroz, is appointed by the coalition as the speaker of Parliament, lawmakers said.

???The ultimatum??¦ is my position and position of the party??™s political council,??? Yosyp Vinskiy, the No. 2 man in the Socialist Party, said Wednesday.

The post of the speaker is the second most important job that is to be decided by the parties while creating the coalition and forming the new government.

The development deals a blow towards earlier plans by Our Ukraine, the Socialist Party and a group led by former Prime Minister Yulia Tymoshenko to create the coalition on Wednesday.

Tymoshenko, whose party controls the largest number of seats among the likely coalition partners, was widely expected to take the post of the prime minister. Our Ukraine, the second largest group, was expected to take the post of the speaker.

This is the second break in the parliamentary sessions taken by lawmakers over the past two weeks showing the challenges the parties face while creating the coalition.

The three parties control 243 seats in 450-seat Parliament, but only 227 lawmakers voted to postpone the sessions, suggesting a brewing split among some pro-Western lawmakers.

As a further evidence of the split, some lawmakers from Our Ukraine and the Tymoshenko Bloc later Wednesday joined forces with some lawmakers from the Regions Party to create an informal group.

The Stability in Ukraine, as the group is to be known, apparently numbers 37 lawmakers that will be led by Anatoliy Kinakh, an Our Ukraine lawmaker. It includes prominent figures, such as Tariel Vasadze, an owner of Ukraine??™s largest car maker ZAZ and a member of the Tymoshenko Bloc and other wealthy businessmen.

The group does not mean the lawmakers have already quit their respective parties, but it is an indication that wealthy lawmakers have been seeking alliances with their counterparts from the Regions Party.

It could play a role and tilt balances in Parliament in the face of a looming dismissal of the legislature by President Viktor Yushchenko if parties fail to create the coalition by the deadline of June 26.

???The group is created to form smart rules for the economy??™s competitiveness on the basis of cooperation with the president and the future coalition government,??? Kinakh said.

Meanwhile, the refusal to back the coalition agreement by the Socialist Party came hours after party leaders made a significant progress towards the coalition at an almost 6-hour meeting with President Viktor Yushchenko.

Yushchenko, who has been visiting the Netherlands on Wednesday, suggested that Our Ukraine, the second largest group in the coalition, not the Socialist Party, should have taken the speaker post.

???Participants of the coalition talks should be guided by results of Parliamentary election,??? Yushchenko said. ???This would be the best demonstration of respect toward the will of the people,??? he said. ???I believe this principle has been broken.???

Yushchenko said he plans to hold another meeting with party leaders upon his return to Kiev.

This is the second time the Socialist Party has changed its position on a major issue over the past two weeks undermining the talks over the coalition.

Last week, the party has reportedly flip-flopped its position on the country??™s future cooperation with NATO away from rapid integration into the alliance. (tl/ez)