Negotiators from the UK and European Union (EU) were meeting face to face in an effort to intensify talks on a post-Brexit trade deal.
However, Downing Street has had to defend the appointment of Boris Johnson’ chief EU negotiator to the key post of national security adviser (NSA).
The Prime Minister faced criticism that unlike previous holders of the post, David Frost is a political adviser rather than a career civil servant, and lacks security experience.
European Commission spokesman Daniel Ferrie said: “Our overall message this week, but also for the coming weeks and coming months, is to intensify our negotiations in order to make progress in order to get a deal.”
Mr Ferrie said he had “no particular comments to make” about Mr Frost being given a second job while the negotiations continued.
He added: “From our side at least we are fully concentrated on the negotiations.”
Teams led by the Prime Minister’s Europe adviser David Frost and the EU’s Michel Barnier were meeting in Brussels for the first time since the coronavirus crisis forced talks to be held remotely.
The meeting comes just a day after it was announced that Mr Frost would replace Sir Mark Sedwill as national security adviser alongside his responsibilities on Europe.
Mr Frost will take up the new role at the end of August but promised the talks with the EU “remain my top single priority until those negotiations have concluded, one way or another”.
Boris Johnson hopes the UK-EU talks could result in a deal by the end of July, although both sides have acknowledged the end of October is when an agreement needs to be concluded in order to ratify it this year.
The current transition period expires at the end of the year, meaning new arrangements will need to be in place or the UK will follow World Trade Organisation rules for its relationship with the EU.