The Continuity IRA (CIRA) was today accused of executing two former members in Belfast earlier this year after they established a rival group.
Northern Ireland ceasefire watchdog the Independent Monitoring Commission (IMC) alleged in its latest report that the hardline republican group killed Edward Burns and Joseph Jones in Belfast last March.
It also blamed the Irish National Liberation Army (INLA) for the murder of nightclub doorman Brian McGlynn in his bed in Derry in June.
The IMC said Mr Burns and Mr Jones were "both former Belfast members (of the Continuity IRA) who had established a rival group in the same area".
"A third person was injured in the same attack," the IMC added.
The body of Mr Burns (36) from the republican Ardoyne area was found in the Bog Meadows area of west Belfast, while the badly beaten corpse of Mr Jones, aged 38, from Poleglass was found in an alleyway off Elmfield Street in the north of the city.
The CIRA was also linked to a mortar device which was discovered in Lurgan in March by police before it could be used and to a range of criminal activity including keeping brothels, drug dealing, extortion, robbery, fuel smuggling and money laundering.
Some of the proceeds went to individual members but some also to the CIRA which the commission said remained active, dangerous and committed.
The IMC also accused the INLA of shooting dead 28-year-old Mr McGlynn in June and said it was involved in criminal activity on both sides of the border.
This included providing services for and protecting criminal gangs in Dublin.
In Belfast, Derry and Strabane members had been involved in patrols against anti-social behaviour and had taken action against a number of drug dealers.
"Overall, therefore, our view remains essentially unchanged. The INLA retains a capacity for extreme violence," the four member commission concluded.
"We cannot rule out it becoming more dangerous in the future and in the meantime it is largely a criminal enterprise."
The Real IRA, the organisation behind the 1998 Omagh bomb, engaged in low level paramilitary activity, targeting police officers and buildings and threatening criminals in west Belfast, the commission said.
Planned operations in Lurgan and Craigavon were frustrated by the police but despite the reduction in activity the group sought to enhance its capabilities by training members in a range of terrorist activities, trying to recruit new members and acquiring weapons and ammunition.
The small dissident republican group Oghaigh na hEireann remained active over the six months, throwing a pipe bomb at a police station in Strabane in July and planting devices at the homes of a PSNI officer and members of the local district policing partnership in the town, according to the commission.
It was unable to attribute to any hardline republican group the planting of devices on a railway line in the border city of Newry in July.