Fresh concerns around Northern Ireland have been raised following Theresa May's resignation announcement.
Sinn Féin leader Mary-Lou McDonald says that Mrs May's decision to stand aside on June 7 is not hugely surprising given the "chaotic situation" around Brexit in Britain.
Hitting out at the way Brexit has been handled she said the Conservative party now needs a "dose of reality".
However, she warned that Mrs May's resignation could have significant implications for Northern Ireland talks centred around getting the institutions back up and running again.
Taoiseach Leo Varadkar and Mrs May were due to meet before the end of this month to review progress made between the political parties on breaking the political deadlock in Northern Ireland.
However, Ms McDonald said Mrs May stepping aside will make "a difficult situation all the more difficult".
"There was to be a review of progress on the Northern talks at the end of May I think we now have to question whether that review will go ahead. I think we need clarity on that point very quickly, we are very anxious that progress is made. The current stalemate is simply not sustainable," said Ms McDonald after casting her vote in today's elections.
Turning to Brexit, she said a change of prime minister will not mean any softening of the backstop or the withdrawal agreement: "The reality is, irrespective of who is prime minister and irrespective of who leads the Tory party, Irish interests need to be protected that's not going to change. I think the Tories need a dose of reality, I think if they imagine that if by changing their leader and by changing prime minister that they can change the fundamental bottom line in respect of Ireland that they are wrong."
Meanwhile, Arlene Foster has paid tribute to Theresa May’s “selfless service” to the UK.
The Democratic Unionist leader, who struck a confidence and supply deal with Mrs May to keep her in power in the wake of the 2017 general election, praised the outgoing Prime Minister’s “dutiful approach”.
Mrs Foster and party colleagues have been particularly critical of Mrs May in recent months for her handling of the Brexit process.
Whilst at times there were differences in our approach, particularly on Brexit, we enjoyed a respectful and courteous relationship
They were vociferously opposed to the contentious border backstop element of the deal the Conservative leader struck with the EU, claiming it would see Northern Ireland treated differently to the rest of the UK.
The Westminster arrangement which saw the DUP’s 10 MPs vote with the Government on key issues delivered a £1 billion funding package to Northern Ireland.
Commenting on Mrs May’s resignation announcement, Mrs Foster said: “After the general election in June 2017, we worked with the Prime Minister and her team through the confidence and supply agreement.
“Whilst at times there were differences in our approach, particularly on Brexit, we enjoyed a respectful and courteous relationship.
“In particular, I commend and thank the Prime Minister for her dutiful approach on national issues and her willingness to recognise Northern Ireland’s need for additional resources through confidence and supply arrangements.
“I pay tribute to her selfless service in the interests of the United Kingdom and wish her well for the future.”
DUP deputy leader Nigel Dodds, who leads the party at Westminster, tweeted: “Whilst we have had differences with Theresa May on Brexit, I have always found the Prime Minister very courteous and pleasant to work with on a personal basis.
“I thank her for her public service and wish her well.”