Question: When did a paramilitary offshoot of the IRA start carrying ut bombings, after splitting from the Real IRA?

Context articles: Dissident Irish Republican campaign
Timeline of Real Irish Republican Army actions
Marwan Barghouti
Denis Donaldson
2009 Massereene Barracks shooting
Óglaigh na hÉireann (Real IRA splinter group)
1972 and 1973 Dublin bombings
New Guard
Real Irish Republican Army
Michael McKevitt

Since the Provisional Irish Republican Army (IRA) called a ceasefire and ended its armed campaign in 1997, breakaway groups opposed to the ceasefire ("dissident Irish republicans") have continued a low-level armed campaign against the British security forces in Northern Ireland.
 The main paramilitaries involved are the Real IRA, Continuity IRA and Óglaigh na hÉireann.
 They have targeted the British Army and Police Service of Northern Ireland (PSNI, successor of the Royal Ulster Constabulary) in gun and bomb attacks, as well as with mortars and rockets.
 They have also carried out bombings that are meant to cause disruption.
 However, their campaign has not been as intensive as the Provisional IRA's.
This is a timeline of actions by the Real Irish Republican Army, also called the Real IRA, an Irish republican paramilitary group.
 The group was formed in late 1997 by members of the Provisional Irish Republican Army who disagreed with that organisation's ceasefire.
Marwan Hasib Ibrahim Barghouti (also transliterated al-Barghuthi; Arabic: مروان حسيب ابراهيم البرغوثي‎ ‎ ; born 6 June 1959) is a Palestinian political figure convicted and imprisoned for murder by an Israeli court.
 He is regarded as a leader of the First and Second Intifadas. Barghouti at one time supported the peace process, but later became disillusioned, and after 2000 went on to become a leader of the Second Intifada from the West Bank.
 Barghouti was a leader of Tanzim, a paramilitary offshoot of Fatah.
Denis Martin Donaldson (1950 – 4 April 2006) was a volunteer in the Provisional Irish Republican Army (IRA) and a member of Sinn Féin who was murdered following his exposure in December 2005 as an informer in the employ of MI5 and the Special Branch of the Police Service of Northern Ireland (formerly the Royal Ulster Constabulary).
 It was initially believed that the Provisional IRA were responsible for his killing although the Real IRA claimed responsibility for his murder almost three years later.
On 7 March 2009, two off-duty British soldiers of 38 Engineer Regiment were shot dead outside Massereene Barracks in Antrim town, Northern Ireland.
 Two other soldiers and two civilian delivery men were also shot and wounded during the attack.
 An Irish republican paramilitary group, the Real IRA, claimed responsibility.
Óglaigh na hÉireann (ONH; ] ) is the title taken by a small dissident Irish republican paramilitary group that has taken part in the dissident Irish republican campaign.
 The organisation started carrying out attacks around 2009 and was formed after a split within the Real IRA.
Between 26 November 1972 and 20 January 1973, there were four paramilitary bombings in the centre of Dublin, Ireland.
 Three civilians were killed and 185 people were injured.
 No group ever claimed responsibility for the attacks and nobody was ever charged in connection with the bombings.
 The first bombing in Burgh Quay may have been carried out by former associates of the Littlejohn brothers who were Secret Intelligence Service provocateurs, in a successful attempt to provoke an Irish government clampdown against the Provisional IRA, while the other three bombings were possibly perpetrated by loyalist paramilitaries, specifically the Ulster Volunteer Force (UVF), with British military or intelligence assistance.
 The UVF claimed in 1993 to have carried out the 1974 Dublin and Monaghan bombings which incurred the greatest loss of life in a single day throughout the 30-year conflict known as the Troubles.
The New Guard was formed in Sydney, Australia in February 1931 as a paramilitary offshoot from a conservative tradition defending loyalty to King and Empire, sound government, law and order, individual liberty and property rights.
 In particular, the movement was formed in response to the policies adopted by Jack Lang, the leader of the Labor Party and Premier of New South Wales It was led by Lt. Colonel Eric Campbell, a First World War veteran.
 The New Guard declined rapidly following Lang's dismissal in May 1932, with its remaining members becoming increasingly inclined towards fascism.
 Still led by Campbell, the movement unsuccessfully attempted to enter parliament at the 1935 state election (running as the Centre Party), but disbanded completely shortly after.
The Real Irish Republican Army or Real IRA (RIRA), is a dissident Irish republican paramilitary organisation which aims to bring about a united Ireland.
 It formed in 1997 following a split in the Provisional IRA by dissident members, who rejected the IRA's ceasefire that year.
 Like the Provisional IRA before it, the RIRA sees itself as the only rightful successor to the original Irish Republican Army and styles itself as "the Real Irish Republican Army" in English or "Óglaigh na hÉireann" in Irish.
 It is an illegal organisation in the Republic of Ireland and designated as proscribed terrorist organisation in the United Kingdom and the United States.
Michael McKevitt (born 4 September 1949) is an Irish republican who was convicted of directing terrorism as the leader of the paramilitary organisation, the Real IRA.