< ! -- Deleted image removed : In July 1983 , the East Tyrone Brigade carried out a landmine attack on an Ulster Defence Regiment ( UDR ) mobile patrol near Ballygawley , killing three UDR soldiers ( a fourth UDR soldier died later ) . In 1985 and 1986 , the East Tyrone Brigade carried out two attacks on RUC bases in their operational area , described by author Mark Urban as " spectaculars " . The first was an assault on Ballygawley base in December 1985 . Two RUC officers were shot dead and the base was raked with gunfire before being destroyed by a bomb . The second was an attack on the part-time base at The Birches , County Armagh , in August 1986 . The base was raked with gunfire and a JCB digger with a 200 lb ( 91 kg ) bomb in its bucket was driven through the perimeter fence . The bomb detonated , destroying much of the base and damaging nearby buildings . In April 1987 the brigade shot and killed Harold Henry , one of the main building contractors to the security forces in Northern Ireland
a landmine attack
Ballygawley land mine attack
Provisional IRA East Tyrone Brigade