Victims of IRA violence have joined together to write an open letter to the Mayor of New York, urging him to apologise for honouring Gerry Adams.
ill de Blasio caused outrage after he renamed this year's St Patrick's Day in celebration of the former Sinn Fein leader.
The Democrat also praised Mr Adams's "goal of a united Ireland", claiming it made "so much sense".
Relatives of people killed by the IRA have now written to the mayor, accusing him of having "callous disregard" for their feelings. They have demanded a public apology, a face-to-face meeting and for Mr Adams's award to be withdrawn.
The letter has been signed by six people - from the two main communities - who lost loved ones in the Troubles.
They include Ann McCabe, the widow of Detective Garda Jerry McCabe, who was shot dead by the IRA in Co Limerick in 1996, and Michelle Williamson, whose parents George and Gillian died in the 1993 Shankill bomb.
The letter states that victims have been "deeply hurt, offended and bewildered" by Mr de Blasio's actions.
They tell the mayor: "We are astounded at your level of naivety and callous disregard for the tens of thousands of innocent victims/survivors of PIRA's murderous terrorist campaign which spanned over four decades."
Mr Adams, who has always denied being a member of the IRA, received the honour at a St Patrick's Day breakfast event in New York on March 17 attended by Taoiseach Leo Varadkar.
The proclamation read: "I, Bill de Blasio, Mayor of the City of New York, do hereby proclaim March 17, 2018 in the city of New York as 'Gerry Adams Day'."
However, the move angered many victims of IRA terrorism.
The letter adds: "The man you have lauded was the president of the provisional republican movement; he is effectively 'commander in chief' of an organisation which brought misery to lives from across the community, across the island of Ireland and beyond.
"Have you any understanding of the impact your actions have had upon those of us whose lives were devastated by the Provisional IRA's murderous actions?
"Remember, this is the organisation which Mr Adams has provided 'political' cover for, whose members he has carried coffins and the organisation for which lead intelligence sources state Mr Adams was himself a member holding key leadership roles."
Mrs McCabe said she signed the letter because she is disgusted by Mr de Blasio's actions.
"I think it's disgraceful that this man (Mr Adams) has been honoured by the Mayor of New York - I feel very strongly about this," she added.
In 2006, Mrs McCabe confronted Mr Adams at a New York fundraiser, asking him to condemn her husband's killing. Unhappy with his reply, she walked out.
She added: "This is a man who refused to condemn the people who murdered my lovely husband. A Gerry Adams Day - how disgusting is that?
"I think he (Mr de Blasio) needs to explain himself, but I don't expect to receive an explanation.
"Did he actually look at Adams's past?
"But then some Americans are very blinded to Adams's past."
Other signatories of the letter include David Kelly, the son of Irish soldier Pte Patrick Kelly, who was killed in the Don Tidey kidnap incident in Leitrim in 1983, and Maura Babington, the widow of James Babington, who was killed off the Antrim Road in Belfast in 1989.
The final two are Pam Morrison, whose three brothers Ronnie, Cecil and Jimmy Graham were killed in separate incidents in south Fermanagh, and Shelley Gilfillan, whose brother Kenneth Smyth and uncle Lexie Cummings were both killed.
Mr de Blasio has not responded to repeated requests for comment.
But Kenny Donaldson, spokesman for the Innocent Victims United group, said he has questions to answer.
"He should remember the ruthless organisation which the Provisional Movement was - they murdered almost 2,000 people, and maimed tens of thousands of others through physical and mental scars," he said.