The DUP leader, Ian Paisley, has welcomed Jeffrey Donaldson's decision to resign from the Ulster Unionists.
It is understood Donaldson, who has rowed for many years with the Ulster Unionist leadership, is now considering joining Paisley's party.
Two newly-elected assembly members Arlene Foster and Norah Beare will leave with him.
The UUP says that Donaldson's resignation was a matter of regret but came as no surprise.
