The British Government is understood to be considering the return of independent monitors to scrutinise paramilitary groups in Northern Ireland.

Northern Ireland Secretary of State Theresa Villiers is expected to make a statement on the current political crisis in the Commons tomorrow.

Last week, First Minister Peter Robinson stood aside - along with three other Democratic Unionist Party (DUP) ministers.

It followed the arrest of three leading republicans - including Sinn Féin's northern chairman Bobby Storey - as part of the investigation into the murder of Kevin McGuigan.

The PSNI has linked the murder to the IRA.

Sinn Féin has blamed the crisis at Stormont on a row between the DUP and the Ulster Unionist Party.