Some relatives of the victims are unhappy with the way Omagh District Council has decided to word inscriptions on the memorials at the bomb site in Market Street and at the nearby Garden of Remembrance, because they claim it does not properly acknowledge who was behind the attack.
The memorial at the bomb site does not mention the perpetrators and text at the garden says the victims were "murdered by a dissident republican car bomb" - but the phrase is placed in inverted commas and attributed to the Omagh Support and Self Help group.
The families claim this indicates the Sinn Fein-dominated council is not prepared to acknowledge republicans were responsible for the atrocity.
However, the council has defended its decision, saying the memorials were recommended by an independent fact-finding group.
Omagh Support and Self Help is holding its own alternative commemoration event on Sunday.
Friday's council memorial involved a 45-minute ceremony beside the newly-built memorial garden, which is close to the bomb site.
Stormont Deputy First Minister Martin McGuinness and Irish Taoiseach Brian Cowen attended and former Lebanon hostage Terry Waite addressed the crowd.
Representatives from the Spanish government were also there to remember an exchange student and youth leader from Madrid who died in the bombing.
Those taking part paused for a minute's silence at 3.10pm - the time the 500lb car bomb exploded 10 years ago.
A new "garden of light" was opened and a glass obelisk memorial at the bomb site unveiled.
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