Britain's Prime Minister Theresa May and her husband Philip are welcomed by staff inside 10 Downing Street, in London, Britain June 9, 2017. (Reuters)
British Prime Minister Theresa May will return to Brussels for Brexit talks this weekend as the United Kingdom and European Union strive to do a deal in time for Sunday's summit of European leaders.
The PM said progress had been made during discussions with EU officials on Wednesday and she hoped to reach a deal "in the interests of all our people".
But the BBC's Laura Kuenssberg said the process was "not going to plan".
Spain has said it will not agree to the Brexit deal unless changes are made to the wording over Gibraltar.
The EU is in a race against time to complete the text of its declaration on future relations with the UK, amid concerns from several member states.
German Chancellor Angela Merkel has indicated she will not attend Sunday's meeting of European leaders - which has been called to approve the draft terms of the UK's withdrawal - unless the text on future co-operation is agreed in advance.
The BBC's Adam Fleming said the timetable was not going to plan, both sides having hoped to agree the document initially on Tuesday and then again on Wednesday.
He said the "real deadline" in Brussels to get an agreement and ensure Sunday's summit went ahead was now considered to be Friday morning - when ministerial aides meet.
After an hour of talks with European Commission President Jean-Claude Juncker, Mrs May sought to strike an upbeat note but signalled talks were set to continue until the eve of Sunday's summit.
"We've made further progress and as a result we have given sufficient direction to our negotiators, I hope, for them to resolve the remaining issues and that work will start immediately," she said.
"I now plan to return for further meetings on Saturday to discuss how we can bring to a conclusion this process and bring it to a conclusion in the interests of all our people." (BBC)