The U.K. and EU leaders from 27 member countries will gather for a final round of talks in Brussels for Brexit special summit on Sunday.
The special EU Council meeting will evaluate the latest developments on Brexit, while the EU leaders are expected to sign off on the withdrawal agreement and the political declaration on Brexit.
Since Prime Minister Theresa May finalized her Brexit withdrawal agreement on Nov. 13, it has faced mass criticism from within her party and from the opposition Labour Party, with two of her Cabinet ministers resigning in protest.
May finalized the 585-page Brexit withdrawal agreement on Nov. 13 that her Cabinet reluctantly agreed to support.
On Thursday, the European Council President Donald Tusk tweeted that a draft document shaping the post-Brexit relationships between the U.K. and EU has been principally agreed by the parties.
Tusk also announced that the negotiators have reached an agreement on a joint text on the U.K.'s future relations with the EU, but he also underlined that this text now needed approval by the EU leaders.
Following the summit, the final deal and the non-binding political declaration will face a critical vote in the House of Commons.
The border issue between the EU-member Ireland and Northern Ireland -- which is attached to the U.K. -- is also one of the key issues of the summit.
The U.K. -- which is set to leave the bloc in March 2019 -- has decided to leave the EU with a referendum on June 2016.
Spain's reservations about the status of Gibraltar was another big hurdle ahead of the extraordinary Brexit summit.
On the issue of Gibraltar, May said on Thursday she spoke last night with Spanish Prime Minister Pedro Sanchez, adding that she is confident that on Sunday we will be able to agree on a deal that delivers for the whole U.K. family, including Gibraltar.
Sanchez previously said Spain would vote against the Political Declaration as it is not happy with the clause regarding Gibraltar's future relations with the EU.
Gibraltar -- a British overseas territory with a population of around 30,000 -- was ceded to Britain by Spain under the 1713 Treaty of Utrecht, but Spanish claims over the region continued. In referenda in 1967 and 2002, the Rock's public widely rejected proposals for it to be governed by Madrid.
Spain is demanding that future EU talks with the U.K. do not cover Gibraltar, and it wants to have the final say over any future arrangements in that regard.
Source: Anadolu Agency