British Prime Minister Theresa May on Sunday defended the Brexit draft agreement with the European Union and said the coming week would be critical for the United Kingdom’s future, the BBC reported.

Ahead of a summit on November 25, May suggested that agreeing on more details of the country’s future ties with the European Union could satisfy the concerns of her Conservative Party MPs who are opposed to the plan. To the ministers calling for a change of leadership, she said, “It is not going to make the negotiations any easier and it won’t change the parliamentary arithmetic.”

“This isn’t about party politics, this is about what matters for this country, it is about what is in the national interest, that’s what I’m determined to deliver,” she said on Twitter. “A deal that’s good for the people of this country.”

The UK is due to leave the European Union on March 29, 2019. After months of negotiations, UK and EU officials agreed on the draft text of a Brexit agreement last week. While the details of the agreement have not been made public, some information was later leaked to the media.

Although May has the support of her Cabinet, voices of dissent have grown in the last week. Four British government ministers, including Brexit Secretary Dominic Raab, resigned after the draft agreement was signed. Raab said the UK was being bullied by the European Union.

May said discussions were continuing to include more details into the future deal proposals, saying it was this part that “delivers on the Brexit vote”. She will also meet European Commission President Jean-Claude Juncker in Brussels, Belgium, ahead of the summit.

Meanwhile, European Union chief negotiator Michel Barnier met diplomats from the 27 remaining member-states and has proposed December 31, 2022, as the deadline for any possible extension to the transition period.