Prime Minister Theresa May is poised to meet outgoing US President Barack Obama in Berlin as he is set to wrap his farewell EU trip. Obama will also meet leaders of Spain, France, Italy and Germany on the final leg of his tour on Friday, 18 November.

May and Obama are expected to discuss the raging conflict in Syria and the ceasefire situation during their talks. "The issue that...will be raised here again is the issue of them [Islamic State fighters] being dispersed around other countries in Africa and parts of the Middle East, not specifically back to the UK," said a Downing Street spokesperson.

"As we close down Daesh's [Islamic State/Isis] areas of operation in one part of the world we need to be mindful of the fact that they may regroup in other parts and how we set about tackling that. Obviously, the issue of Daesh fighters who've been in either Syria or Iraq returning to Europe is a matter of grave concern."

Asked whether the leaders would jointly issue any condemnation against Syrian President Bashar al-Assad, the spokesperson responded: "We will clearly push how we resolve the situation in Syria, we must be united in calling for a sustained ceasefire."

European leaders are also expected to caution Obama's successor, Donald Trump, against easing the economic sanctions against Russia. This is also the first time the European heads of state are meeting face-to-face to talk about the outcome of US presidential elections.

The presence of key leaders — five of the G7 members — in Berlin will provide a platform for an informal summit to touch upon other vital global issues such as Nato and tackling Russia as well. Talks over Brexit are unlikely to come up when the British and American leaders meet but it is bound to surface when May meets other European heads of state.

While the British prime minister is to hold separate talks with the German Chancellor Angela Merkel to negotiate Brexit plans, no such meeting has been scheduled with leaders of France, Spain and Italy. "In the margins of the meeting almost certainly it will crop up in [the] discussion. Brexit will be part of it, I'm sure," the No 10 spokesperson said.

May's discussions with the EU leaders come at a crucial time when the EU authorities have sent signals of a hardening stance in the negotiations. German Finance Minister Wolfgang Schauble told the Financial Times that Britain may have to pay into EU budgets for more than a decade even though it secedes from the union. "Possibly there will be some commitments that last beyond the exit ... even, in part, to 2030," said Schauble.