The European Union "stands ready to examine whether any further assurance can be provided" to Britain over the Irish backstop and their tentative divorce agreement, a draft seen by Reuters shows.
The draft, a six-point document the EU is preparing for British Prime Minister Theresa May on Thursday to help convince the divided UK parliament to approve their Brexit deal, said any such assurances would not "change or contradict" the agreement.
"Irish backstop does not represent a desirable outcome for the Union... is only intended as "insurance policy," the draft statement says.
The other 27 EU states have not yet agreed on much of the text and diplomatic sources said especially the paragraph on the EU's readiness to provide more assurances to Britain was likely to change later in the day because of opposition from Ireland as well as other bloc members.
The draft statement also says if the backstop is triggered, the EU would use its "best endeavours" to agree swiftly on deal to replace the backstop.
"If backstop is applied it would apply only temporarily, unless and until a new EU-UK agreement is in place," the statement adds.
EU leaders will today consider how they can help get the UK Brexit deal - which still faces a wall of opposition in the London parliament - ratified by UK MPs.
Embattled British Prime Minister Theresa May will receive a warm welcome from her 27 EU counterparts after winning a no-confidence by her Conservative Party colleagues.
But as Leo Varadkar joins the leaders in Brussels for yet another summit, diplomats insist the draft deal - signed off by member state governments on November 25 - cannot be reopened. Any support measures will focus on "interpretation and elaboration".
EU summit chairman Donald Tusk said the heads of government will give their formal reaction to developments after a dinner meeting tonight.
First, the leaders will hear a report from Mrs May, and thereafter the remaining 27 leaders will discuss the issue.
One diplomat stressed that the EU-UK Withdrawal Agreement was between the other 27 members of the trade bloc and the London government.
That meant any change of leadership - be it via personnel or the installation of a new ruling party - did not change the status of what was agreed.
The EU leaders' summit was called to advance the framing of another seven-year funding plan spanning the years 2021-2027 inclusive. The agenda also covered co-operation on dealing with inward migration, and better economic governance for the EU single currency, and member states' economies generally.
These issues will be variously discussed today and tomorrow but Brexit, and that report from Mrs May, will overshadow this work because the decisions in the EU's second largest economy will affect all future plans.
But, despite continued negative reactions from London, it is clear some goodwill persists towards Mrs May.
Hopes of unlocking the Brexit deadlock focus on the accompanying political declaration, which sets out guidelines on big picture EU-UK trade talks after Brexit happens and transition periods expire.
"We know what is impossible: re-negotiating the deal. Everything else is possible," one Brussels diplomat said.
However, EU officials continued to insist that preparations for a no-deal Brexit, emerging from the ongoing UK conflict will continue.
Here, the EU signals Brussels has a co-ordinating role in no-deal Brexit preparations, but individual governments must carry the burden.
"No-deal preparations from Ireland to Poland to Italy are the concerns of the individual member states, not the European Council.
"It is the role of the commission to work on a common framework, so this issue is a question for the Irish Government and for the commission," one EU source said.