DUBLIN — Irish Republican Army dissidents are posing their greatest security threat in Northern Ireland since the province’s peace accord 11 years ago — and are receiving help from a handful of IRA veterans in plotting gun and bomb attacks, an expert panel found today.

The Independent Monitoring Commission, which reports regularly on the underground activities of Northern Ireland’s myriad paramilitary groups, said dissidents backed by a "small number" of mainstream IRA members are responsible for a surge in violence since March.