Foster accuses Prime Minister of a 'slapdash' approach to her talks with EU
Theresa May has come under attack from the DUP for seeking a further delay to Brexit, with claims she is taking a "disorganised and slapdash" approach to negotiations with the EU.
The Prime Minister has asked for Brexit to be delayed until June 30, but Brussels is expected to insist on a longer extension.
The UK is due to leave the EU next Friday, but the withdrawal agreement has not been approved by MPs.
Hopes are dwindling that the Government's talks with the Labour Party to try to find a compromise will succeed.
DUP leader Arlene Foster said: "The Prime Minister's latest plea to Brussels for an extension to Article 50 is unsurprising but unsatisfactory. It should not have been like this. Exiting the EU has become chaotic because of intransigence in Brussels and ineffectiveness in London.
"The UK fighting European elections almost three years after a clear majority voted to leave the EU sums up the disorganised and slapdash approach taken to negotiations by the Prime Minister."
Mrs Foster added: "It was foolish strategically in the negotiations to limit the UK's leverage by removing 'no-deal' from the table.
"The Prime Minister should not waste any extension by subcontracting the UK's future to Jeremy Corbyn. This time should be used to get a better deal which works for every part of the UK so the entire nation can leave the EU together."
Alliance deputy leader Stephen Farry said it "beggared belief" that Mrs Foster was unhappy with the extension request.
"The DUP approach is a major contributory factor to the current crisis," he said.
"They have blocked the Withdrawal Agreement and their Malthouse alternative has been debunked as unworkable. Despite all the warnings, they are continuing to enable a catastrophic no deal outcome."
Mr Farry said an extension until only June 30 would not work.
"It does not provide sufficient time for any proper reconsideration of Brexit and brings complications for the EU. It is inevitable they will require a different approach," he added.
TUV leader Jim Allister lambasted the Prime Minister's Brexit approach, and said she should resign.
"The betrayal of Brexit has taken another stride forward with Mrs May's further grovelling plea to the EU to stay even longer," he said.
"Democracy is being shredded by the Prime Minister. With the biggest democratic mandate in our history we instructed parliament and government to leave.
"Three years later the political elite remain in defiance and connive by every conceivable dodge to subvert the will of the people.
"Such might fit exactly with the EU's contempt for national will, but in this UK cradle of democracy it is an indelible stain of totalitarian rejection of the people's vote."
SDLP leader Colum Eastwood welcomed reports that European Council president Donald Tusk was set to propose a year-long delay to Brexit.
He said Brexit had been "derailed by ideological intransigence" from the DUP and their European Research Group allies.
"Their push for a hard Brexit, that will inevitably create a hard border, has killed this version of a deal, but it's also killed their influence over the process," he said.
"The SDLP welcomes European Council President Donald Tusk's proposal for a long delay to Brexit. We have been calling for the British Government to revoke Article 50 and create breathing space to reflect on where this process has taken us."
Sinn Fein MLA Caoimhe Archibald said: "It will be for the EU to decide whether or not a further extension to Article 50 is granted. There should not be an extension without a purpose. The only way to avoid a disastrous crash-out Brexit is through the withdrawal agreement and the backstop it contains."
The Prime Minister wrote to Mr Tusk requesting the Brexit delay, with an option to leave earlier if she can get her deal through the Commons.
Mrs May said she will seek to secure ratification of the deal before EU elections on May 23, but will make "responsible preparations" for the UK to take part in the poll if that does not prove possible.
Her cross-party talks with Labour appear to have stalled, with shadow Brexit Secretary Sir Keir Starmer saying it was "disappointing" that the Prime Minister was refusing to consider changes to her deal.
The request for an extension will be considered at an emergency EU summit on Wednesday where it requires the unanimous agreement of the leaders of the remaining 27 member states.
EU sources said Mr Tusk is recommending a longer postponement of one year, with a break clause in the case of earlier ratification, in a so-called "flextension" deal.
Taoiseach Leo Varadkar said a longer delay to Brexit "might make more sense" than the UK seeking "rolling extensions where there is an extension every couple of weeks or every couple of months because that just adds to the uncertainty for citizens, for businesses and for farmers".