Simplify the following text for a Grade 9 native English-speaking person.
Original: The Omagh bombing was a paramilitary car bomb attack carried out by the Real Irish Republican Army ( RIRA ) , a splinter group of former Provisional Irish Republican Army members opposed to the Belfast Agreement , on Saturday 15 August 1998 , in Omagh , County Tyrone , Northern Ireland .
Simplified: The Omagh bombing was a bomb attack by the Real Irish Republican Army in Omagh , Northern Ireland , on August 15 , 1998 .