BRUSSELS (Reuters) - British Prime Minister Theresa May will meet European Commission President Jean-Claude Juncker and his chief Brexit negotiator in Brussels on Monday, Dec. 4, the EU executive confirmed on Thursday. EU officials hope that May will make new offers to unblock negotiations on a treaty on Britain s 2019 withdrawal from the Union. They say any British move needs to come by around Dec. 4 if leaders meeting at a Dec. 14-15 are to be able to endorse a move to a new phase of talks, to include future trade relations.  On Friday, May will meet European Council President Donald Tusk in Brussels as part of what EU officials describe as a bid to agree the  choreography  of a deal in December. Confirming the Juncker-May meeting, the Commission s chief spokesman told reporters they would discuss Brexit but declined to comment further on the state of negotiations.  Everyone is talking to everyone, already, at all levels,  he said. No comment was immediately available from May s office. Envoys from the 27 other member states agreed on Wednesday to delay by a week until Wednesday, Dec. 6, a meeting to prepare the drafts of the summit conclusions, diplomats said. Those conclusions will determine whether leaders agree that Britain has made  sufficient progress  toward agreeing divorce terms for the summit to approve new talks on a post-Brexit relationship. 