Northern Ireland's First Minister Designate is calling on every community there to show respect in the wake of Queen Elizabeth II's death.
Michelle O'Neill joined other party leaders in signing a book of condolence at Belfast City Hall on Friday.
The 96-year-old British monarch died peacefully on Thursday afternoon at Balmoral in Scotland, Buckingham Palace said.
She was the longest serving monarch in British history.
Sinn Fein's Michelle O'Neill (right) signs a book of condolence for Britain's Queen Elizabeth II at Belfast City Hall. Picture by: Mairead Cleary/NewstalkHer eldest son, Charles, is now king and will be known as King Charles III.
Britain is to observe a period of 'royal mourning' from now until seven days after Queen Elizabeth II's funeral.
Ms O'Neill said she was disappointed to hear of fireworks going off in some parts of Belfast on Thursday night.
The Sinn Féin deputy leader made a plea for tolerance.
"This is a time for everybody to be respectful: Queen Elizabeth has died, there's a family that is mourning her loss.
"She may have been the Queen of England but she was also a mother and grandmother.
"And I think people should be very respectful, this is a time for reflection, this is a time to be respectful of all people and how they feel.
"And certainly I would encourage that, and I would ask everybody to be respectful".
She said people need to be mindful that others are grieving.
"It's really, really important that - particularly at this time - that we're respectful, that we show respect to each other.
"That we understand that people are grieving.
"I understand that, as an Irish person, there are those in Britain and those people here - my neighbours, people who live in this community - who are mourning the loss of their Queen.
"And I think that's really, really important that we're respectful and we acknowledge that".
Britain's Queen Elizabeth II famously shook hands with Sinn Féin's Martin McGuinness (left, front), then-Northern Ireland Deputy First Minister, in Belfast in June 2012. Picture by: REUTERS / Alamy Stock PhotoMs O'Neill said she believed the Queen will be remembered for reconciliation.
"There's no doubt that she leaves a legacy of someone who reached out the hand of friendship, someone who advanced peace and reconciliation - someone who sought to build relationships between those of an Irish and those of a British identity.
"I think that was the starting work at something that I think that she'll be very much remembered for her on this island".
And she said she "looked forward to working with the King, King Charles, whenever he comes in to his role.
"I'm sure that he will carry on the legacy of trying to build relationships between our islands", she added.
Additional reporting: Mairead Cleary
