Sinn Féin has dismissed a proposal to stand independent anti-Brexit candidates as part of a general election pact in Northern Ireland.
The SDLP had suggested parties that supported a Remain vote in last year's EU referendum should strike a deal on candidates for the 8 June poll.
The party's leader Colum Eastwood said putting forward agreed candidates with no party affiliation was an option.
But Sinn Féin's John O'Dowd said this was "not a credible offer".
Some parties opposed to Brexit have held talks about forming what Sinn Féin's Michelle O'Neill described as a "progressive alliance" in some constituencies for the Westminster election.
The aim was to take seats from parties that back the UK's withdrawal from the EU.
The Democratic Unionist Party and the Ulster Unionists, which both voted in the House of Commons to trigger the Brexit process, have also held talks about the chances of agreeing to stand a single unionist unity candidate in some areas.
'Proposal bolsters SDLP'
It is understood that Mr Eastwood's proposal for independent anti-Brexit candidates was to cover the East Londonderry, Fermanagh and South Tyrone and North Belfast constituencies.
But Mr O'Dowd said it would not be backed by Sinn Féin and any pact would be centred on "political party representation".
"We don't believe that's an acceptable way forward," said the Upper Bann MLA.
"It is political parties that will drive forward change in this society.
"We see that as a proposal from Colum to stymie Sinn Féin and bolster the SDLP - that's not what progressive political alliances should be about."
He added that his party was still prepared to talk to others about a possible deal.
'Across the spectrum'
Mr Eastwood acknowledged that "there is probably no chance now" of his proposal becoming a reality.
"If Sinn Féin have ruled that out, I think it's very, very difficult," he said.
"We have always said that we would not do a pact with Sinn Féin alone.
"We wanted this to be broad; we wanted this to be non-nationalist; we wanted to go right across the political spectrum."
On Tuesday, the Green Party said it would not unite with parties that did not share its "vision for a progressive society".
Its leader Steven Agnew said the SDLP's decision to select incumbent MP Alasdair McDonnell as its South Belfast candidate for the snap election ended chances of an agreement in the constituency.