The Ulster Unionist Party has suspended its president the Rev Martin Smyth andtwo other MPs, Mr David Burnside and Mr Jeffrey Donaldson, it emerged tonight.
The move came as a disciplinary committee met for the first time to considerthe future of the three rebel MPs opposed to the leadership of Mr David Trimble andthe Belfast Agreement.
A party source said: "The three have been informed of the decision and they areentitled to attend a disciplinary hearing next month."
The suspension of the three MPs signalled a dramatic escalation in the internalstrife which has created the most serious crisis in the party in 30 years.
The decision followed their resignation of the party whip at Westminsterbecause of their opposition to Mr Trimble and his peace process strategy.
The Rev Smyth once challenged Mr Trimble for the party leadership but MrDonaldson is by far the most outspoken critic of his leader.
The statement read: "Following yesterday's decision by the party officers torefer a suspected breach of party rules by three members of parliament, theparty's disciplinary committee met today at party headquarters in Belfast.
"The committee decided to hold a further formal hearing on July 17 at whichthe three MPs are entitled to be present.
"The committee determined that pending the hearing, Reverend Martin Smyth,Jeffrey Donaldson and David Burnside are suspended from party membership withimmediate effect.
"Under the party rules, anyone suspended from membership ceases to be amember and forfeits all the rights and privileges of party membership."
Mr Donaldson said he was shocked by the move and he and his two colleagues wereseeking legal advice to have their suspensions rescinded.
"I'm absolutely astonished at the decision of the disciplinary committee tosuspend myself and my two parliamentary colleagues from the Ulster UnionistParty," he said.
"We have not been afforded any opportunity to state our case before thisdecision was made.
"I do not think there is any provision in the rules of the Ulster UnionistParty for disciplinary action to be taken against a party member before he hashad the opportunity to have his case heard.
"I believe that this decision can be challenged and we are currently seekinglegal advice."