The range of ministers’ views on Brexit are a “polyphonic chorus” that need to be arranged into a “melody”, Jean-Claude Juncher has said, as he voiced hopes for a deal by November.
The European Commission president warned the negotiations were “not easy” and criticised the “different signals” he was receiving from London.
But he said he was optimistic of a final settlement next month.
It comes as a group of pro-EU political parties from Northern Ireland held crunch talks with Brussels’ chief Brexit negotiator Michel Barnier.
Speaking at the Austrian parliament on Friday, Mr Juncker said: “Negotiations are not easy because we also have to be critical that we receive different signals from London.
“There is a polyphonic chorus at the level of the British cabinet and we try to arrange the pieces… so that they become a melody.”
He added that he hoped EU leaders would make “enough progress” at a summit in two weeks so that “we can see it through in November”.
Britain and the EU are trying to push through two deals – one on the divorce and another on the future relationship.
Brussels has set autumn 2018 as the deadline, saying it needs time for all its institutions to ratify the final agreement before Britain officially leaves the EU on 29 March 2019.
Mr Barnier sat down with four Northern Irish parties – Sinn Fein, the SDLP, Alliance and Greens – to update them on negotiations and listen to their concerns.
A UK Brexit department spokesperson responded: “We will continue to work at pace to conclude these negotiations in the autumn.
“As the prime minister has said, we will set out our backstop proposal that preserves the integrity of the UK.
“It will be in line with the commitments we made back in December.”
A backstop proposal that would see Northern Ireland remain regulatory aligned with the EU was published by Reuters earlier this week.
The pro-Brexit Democratic Unionist Party, which is also propping up the Conservative minority government in Westminster, has warned it would not accept such a proposal.