Unionists have accused Sinn Fein MEP Martina Anderson of "breath-taking hypocrisy" for protesting in the European Parliament against the bombing of Syria.
The DUP, Ulster Unionists and TUV said Ms Anderson had no credibility on the issue and challenged her to condemn IRA bombings.
Explaining yesterday's protest by herself and fellow Sinn Fein MEPs against the attack by Britain, the US and France, Ms Anderson said: "We held up signs calling for an end to the bombing and an end to the war in Syria, which has brought untold misery to millions and created a huge humanitarian crisis."
She also hit out at the "bizarre spectacle" of French President Emmanuel Macron addressing the European Parliament in Strasbourg "about upholding democratic values just days after dropping bombs on Syria".
Ms Anderson said: "What we need to see is a humanitarian response, not a military response which will only add to the pain and suffering."
But UUP MLA Doug Beattie said: "There are many people who oppose the bombing of Syria, and I totally understand their viewpoint. But the breath-taking hypocrisy of a convicted bomber like Martina Anderson, who represents a political party which still condones violence, leaves me rolling my eyes.
"She has no credibility on this whatsoever. When those who bombed Northern Ireland for 40 years try to portray themselves as whiter than white, it is impossible to take them seriously, and most people just switch off.
"Ms Anderson needs to condemn the Enniskillen and Shankill bombings and all the rest before she speaks on this again."
DUP MEP Diane Dodds said: "The hypocrisy of Sinn Fein is astonishing. Martina Anderson, at the age of 18, was charged with possession of a firearm and causing an explosion.
"Ms Anderson was then subsequently arrested along with four of her fellow IRA members and convicted of conspiring to cause explosions in England.
"Yet she has staged a protest in the European Parliament against the legitimate and proportionate bombing of Syria by democratic governments in the US, France and the UK. Sinn Fein has serious questions to answer about the use of violence.
"Ms Anderson retweeting Jeremy Corbyn stating 'Bombs won't save lives or bring about peace', doesn't fool anyone. It is insulting to the many innocent victims.
"Clearly Ms Anderson places a different value on innocent lives lost in Syria to those in Warrington, Brighton or La Mon."
TUV leader Jim Allister said: "For someone convicted of explosive offences to question President Macron's commitment to democratic values would be laughable but for the death and destruction which IRA bombs caused. Sinn Fein's supposed concern for the people of Syria stands in stark contrast to their attitude to the innocent victims of Anderson's IRA.
"You cannot pretend to be concerned about civilians on the other side of the world while naming play parks after a man linked to the brutal sectarian slaughter of Kingsmill.
"It makes a mockery of the tears and heartache of the victims of IRA bombs for an IRA bomber to feign concern about victims of bombs on the other side of the world."