EU leaders are set to extend an olive branch to British Prime Minister Theresa May at a summit in Brussels this week in a bid to break a deadlock in Brexit negotiations.

The Europeans will announce that there has not been enough progress on divorce issues, including the size of Britain's exit bill,  to move on to the second phase, of trade talks, until December at the earliest.

But in a goodwill gesture to a badly weakened British leader, they are set to say that the EU should start internal preparations for talks on the future relationship with Britain, which is due to leave the bloc in 18 months.

"The goal is to be a bit more positive, show London that the door isn't totally closed," an EU diplomatic source told AFP. "But basically it doesn't change anything."

Negotiations have become increasingly bad tempered, with European Commission chief Jean-Claude Juncker saying on Friday that the British "have to pay" and British finance minister Philip Hammond calling the Europeans "the enemy".

Belgian Prime Minister Charles Michel, in an interview published Saturday, urged May's government to "find clarity among themselves as quickly as possible" and overcome divisions over its Brexit policy.

The poisonous atmosphere is not just in the talks -- noxious fumes in the Europa building where the summit is due to be held sickened 20 people on Friday and it is not due to reopen until Monday.

- 'Good cop, bad cop' -

All 28 national leaders will meet on Thursday in Brussels to discuss EU President and summit host Donald Tusk's schedule for discussing Europe's post-Brexit future, with the crisis in Catalonia also likely to rear its head, and relations with Turkey up for discussion.

May will then be asked to leave after breakfast on Friday so the 27 other leaders can weigh up Brexit.

Germany is leading a group of EU countries that want the sensitive issue of Britain's financial commitments to the EU solved before any discussions are opened on a post-Brexit trade deal.

Others want to give Britain something to cling to amid fears that an economically damaging "no-deal" scenario on March 29, 2019 is becoming increasingly likely.

"There are two types of EU countries, those that lie awake at night worrying about Brexit and those who don't," another EU diplomat said.

The EU is demanding progress on three divorce issues -- the divorce bill, the rights of three million citizens living in Britain and the fate of Northern Ireland and its land border with EU member Ireland-- before it will move on to discussing trade talks, as Britain wants.

The EU's chief Brexit negotiator Michel Barnier warned during the last round of EU-UK talks that the negotiations were in a "disturbing" deadlock over the bill, which the EU puts at 100 billion euros ($118 billion) and Britain at 20 billion euros.

A draft summit statement obtained by AFP says that while there has been "progress" it is not enough to unlock the next phase of talks, noting the lack of a "firm and concrete commitment" from Britain on the money.

They will "reassess" in December whether to move to trade, and so to be '"fully ready" for that they authorise Barnier and the member states "to start internal preparatory discussion."

EU sources also played down talk of divisions between Barnier, who reportedly wants to throw Britain a bone, and more reluctant member states.

"Barnier and the EU 27 are taking turns to play Good Cop, Bad Cop," a diplomatic source said.

- Visions of the future -

The bulk of the summit will be devoted to plans to reboot the EU after the shocks of Brexit, the eurozone debt crisis and the migrant crisis.

French President Emmanuel Macron and Juncker have both recently unveiled visions for the future, and Tusk will at the summit outline his plans for making them a reality over the next two years, up to a special EU summit in Romania the day after Britain finally leaves.

German Chancellor Angela Merkel said on Saturday that former Polish premier Tusk will explain "how we can improve our working method to show results more quickly".

The EU leaders may also discuss US President Donald Trump's harsh take on the 2015 Iranian nuclear deal, which prompted France, Germany and Britain to issue a strong rebuttal on Friday, in a sign that cooperation on security and diplomacy continues despite the bad blood over Brexit.

Source: AFP