Sinn Féin has said it intends to challenge the role of the Independent Monitoring Commission in the British and European courts.
The announcement was made at a news conference in Belfast this morning.
Last month, the commission imposed fines on Sinn Féin over continued paramilitary activity by the IRA.
The IMC was set up by the British and Irish governments and is chaired by the former Speaker of the Assembly, Lord Alderdice.
In a hard-hitting report last month, it recommended fining Sinn Féin over ongoing IRA paramilitary activity, and also imposing financial penalties on the Progressive Unionist Party because of loyalist violence.
However, Sinn Féin claims the commission's behaviour breaches the European Convention on Human Rights on at least three counts.
