There are reports in Britain that rebel Conservative MPs have gathered enough support to trigger a vote of no confidence in Prime Minister Theresa May.
Several media outlets are reporting that the threshold of 48 letters of no confidence has been reached.
Tory MP Graham Brady, chairman of the Conservative backbench 1922 Committee, has reportedly asked to meet Mrs May on Wednesday.
However, there has been no official confirmation.
Mrs May has been touring Europe meeting heads of State, as well as EU Council President Donald Tusk, after deferring a House of Commons vote on her Brexit deal that was due to take place this evening.
When asked whether she had been told that the 48 letters had been received, Mrs May said: "No, I have been here in Europe dealing with the issue I have promised Parliament I would be dealing with."
Mrs May was speaking in Brussels after talks with European leaders at which she said there had been a "shared determination" to address the issue of the Brexit backstop.
Mrs May delayed tonight's planned vote after it became clear it would not be passed.
A flurry of Tory MPs have already said they have lost confidence in Mrs May in recent weeks.
European Research Group chairman Jacob Rees-Mogg and others have delivered letters of no confidence in Mrs May, and if 48 are submitted, a leadership contest would be triggered.
Parliament is set to vote on whether to approve Mrs May's Brexit deal before 21 January.
A further meeting of the British cabinet is due to be held tomorrow afternoon.
Hearing that SirGraham Brady has asked to see the PM after #pmqs tmrw, and multiple sources, including senior tories and a cabinet minister, telling us tonight they believe the threshold of 48 letters has been reached - v unlikely to be any confirmation until tomorrow— Laura Kuenssberg (@bbclaurak) December 11, 2018
Earlier, the opposition in the House of Commons sent a joint letter to Mrs May expressing concern about her sudden cancellation of the crunch Commons vote on the Brexit deal.
The letter says: "We believe that this deferral shows a contempt for Parliament.
"You admitted in the House that you are running from a heavy defeat on your deal in the House of Commons.
"It cannot be right that the Government can unilaterally alter the arrangements, once this House has agreed on a timetable, without the House being given the opportunity to express its will."
The letter, signed by Labour's Jeremy Corbyn, SNP Westminster leader Ian Blackford, Liberal Democrat leader Sir Vince Cable, Plaid Cymru's Liz Saville Roberts and co-leader of the Greens Caroline Lucas, demanded assurances from the prime minister on what happens next.
Breaking: Opposition parties have accused the PM of showing contempt for Parliament over the postponed Brexit vote, & set out five Qs for the PM to answer, inc calling on Theresa May to confirm that her deal is dead and that the revised proposal will be substantially different pic.twitter.com/ng3lITlrS1— Labour Whips (@labourwhips) December 11, 2018
The opposition leaders want to know if the Brexit deal is dead and if revised proposals will be substantially different.
They want assurances that the Commons will be given sufficient time to debate the government's negotiating objectives.
DUP leader Arlene Foster earlier told RTÉ News that the backstop must go from the proposed UK Withdrawal Agreement with the EU.
Mrs Foster is due to meet Mrs May tomorrow
Mrs Foster said the UK had made a strategic mistake in its negotiations with Brussels by allowing the Irish border question to be sorted before the UK's future trading relationship with the EU was addressed.
Asked about the fact that three of the DUP's ten MPs at Westminster were from pro-remain constituencies, Mrs Foster said the majority of people in the UK voted to leave the EU and that democracy had to be respected.
She said that the national interest was the most important issue and that her party had signed the Confidence and Supply Agreement with the Conservative government to deliver on Brexit.