The east of the county has a long history of militant Republicanism from Tom Clarke, Joseph McGarrity, Liam Kelly, Gerry McGeough, Tommy McKearney, Bernadette Devlin McAliskey and Martin Hurson. The IRA's heaviest single loss of life since the 1920s involved the East Tyrone Brigade, when a group of eight volunteers were ambushed and killed by the British special forces, the Special Air Service (SAS), during an attack on the Royal Ulster Constabulary (RUC) station at Loughgall on 8 May 1987.
The SAS, however, had set a trap to destroy the unit. They had placed an SAS soldier inside the station, and deployed a squad of 24 soldiers split into six groups around the station building. It has been alleged, but never proved, that the RUC had an informer in the IRA group, and that he was killed by the SAS in the ambush. However, in his book Big Boys' Rules Mark Urban points to the fact that an Ardboe woman, Colette O'Neill, was abducted by the IRA several weeks later, and he hypothesises that she may have been the informer. However she denied this and was released alive.
Just after 7:00 p.m. on 8 May 1987, Declan Arthurs drove the JCB carrying the bomb through the perimeter fence of the RUC station. The van carrying the rest of the IRA unit pulled up and they jumped out and opened fire on the station. The IRA just managed to detonate its 200 lb (900 kg) bomb, heavily damaging the police station, before the SAS opened fire.
The SAS riddled the JCB and the van with bullets. In addition, the car of passer-by Anthony Hughes was fired on by the SAS. Hughes, 36, was killed and his brother badly wounded. Subsequent security forces statements said with regret that they had been innocent passers-by caught in crossfire. All eight IRA guerrillas were killed, all from head wounds. The soldiers fired more than 600 rounds; the IRA men fired 70 rounds but did not hit any of the soldiers. It was later alleged that one of the dead men was in fact an informant for the RUC, although this was denied by security sources, who claimed that the information on the IRA unit was gained from electronic surveillance.
The British recovered eight IRA weapons from the scene – three Heckler & Koch G3 rifles, one FN rifle, two FNC rifles, a Ruger revolver and a Spas-12 shotgun. The Royal Ulster Constabulary linked the guns to 7 murders and 12 attempted murders in the mid Ulster area. One of the guns had been taken from a reserve RUC constable killed two years earlier.
The innocent civilian, Anthony Hughes, who was shot dead by the SAS, had been traveling in a car with his brother, Oliver, unaware of the ambush. Unfortunately, both were wearing blue overalls similar to those sometimes worn by IRA members on operations and so were mistaken for IRA men engaged in the attack. As they attempted to reverse out of the gunfire, SAS troopers positioned nearby mistook them as part of the IRA unit and opened fire. Forty shots were aimed at the car, killing Anthony and wounding his brother. Hughes' widow later received compensation from the British Government for the death of her husband.
Thousands of people attended the funerals of the dead IRA men, the biggest republican funerals in Northern Ireland since those of the IRA hunger strikers of 1981. Gerry Adams in his graveside oration said the British Government understood that it could buy off the government of the Republic of Ireland, which he described as the "shoneen clan" (pro-British), but "it does not understand the Jim Lynaghs, the Pádraig McKearneys or the Séamus McElwaines. It thinks it can defeat them. It never will.
In 2001 the European Court of Human Rights ruled that ten IRA members, including the eight killed at Loughgall, had their human rights violated by the failure of the British government to conduct a proper investigation into the circumstances of their deaths.
In August 1988, an SAS ambush killed IRA members Gerard Harte, Martin Harte and Brian Mullin as they tried to kill an off-duty Ulster Defence Regiment member. Michael "Pete" Ryan, an alleged top Brigade's member , led an IRA flying column during a large operation against a checkpoint at Derryard, in December 1989. Two British soldiers were killed in action. On 11 February, 1990 the Brigade managed to shoot down a Lynx helicopter near Clogher by machine gun fire. In October 1990, two more IRA men, Dessie Grew and Martin McCaughey, were shot dead near Loughgall by undercover soldiers. In June 1991, three IRA men, Lawrence McNally, Peter Ryan and Tony Doris, died in another SAS ambush at Coagh, where their car was raked with gunfire. The RUC stated the men were on their way to mount an ambush on Protestant workmen.
In January 1992, East Tyrone Brigade members killed eight building workers and severely injured another six, with a landmine at Teebane near Omagh. One of the workers killed, Robert Dunseath, was also a member of the Royal Irish Rangers. The men were working to re-build British Army bases damaged by IRA bombs. The men were all Protestants and this was widely perceived as a sectarian attack.
Another four IRA members were killed in February 1992. The four, Peter Clancy, Kevin Barry O'Donnell, Sean O'Farrell and Patrick Vincent, were killed at Clonoe after an attack on the RUC station in Coalisland. Whereas the previous ambushes of IRA men had been well planned by British special forces, the Clonoe killings owed much to the inexperience of the IRA men in question. They had mounted a heavy DShK machine gun on the back of a stolen lorry, driven to the RUC/British Army station and opened fire with tracer ammunition at the fortified base. They then drove past the house of Tony Doris, the IRA man killed the previous year, where they fired more shots in the air and were heard to shout, "Up the 'RA, that's for Tony Doris". This gave ample time for the British Army to respond. The IRA men were intercepted by the British Army as they were trying to dump the lorry and escape in cars in the car park of Clonoe Roman Catholic church. Two IRA men got away from the scene, but the four named above were killed. One witness has said that some of the men were wounded and tried to surrender but were then killed by British soldiers.
In addition, the IRA in Tyrone was the victim of an assassination campaign carried out by the loyalist paramilitaries of the Ulster Volunteer Force (UVF). The UVF killed 40 people in east Tyrone between 1988 and 1994. Of these, most were Catholic civilians with no paramilitary connections but six were Provisional Irish Republican Army members. Three of them were killed in a pub in Cappagh in March 1991. The IRA responded by killing senior UVF man and former UDR member Leslie Dallas.
An IRA bomb attack against British Paratroopers, also near Cappagh, during which a soldier lost both legs, triggered a series of clashes between troops and local residents in mid-May 1992. The riots lasted for several days, ending with the paratroopers' assault on three bars, where they injured seven civilians. Another street fracas between a King's Own Scottish Borderers platoon and Republican sympathizers in Coalisland resulted in the theft of an army machine gun, later recovered nearby.
Six Paratroopers were charged with criminal damage in the aftermath, but they were later acquitted.
From mid-1992 up to the 1994 cease fire, the Brigade was still able to keep pressure on British forces in the region, despite its heavy losses. The East Tyrone unit executed a total of eight mortar attacks against British security facilities and was also responsible for at least sixteen bombings and shootings, killing four members of the security forces during the same period.