European Commission vice president Maroš Šefcovic has told political group leaders in the European Parliament that technical discussions with the UK on the Northern Ireland Protocol are progressing and that the UK was engaging on the issues "in good faith".
Two sources have also confirmed that Mr Šefcovic's UK opposite number Lord Frost has accepted an invitation to travel to Brussels for dinner with Mr Šefcovic on Thursday evening.
It is understood Mr Šefcovic told the European Parliament's Conference of Presidents, made up of the political group leaders, that while technical talks on the protocol were proceeding positively, there were some 27 issues that remain outstanding.
He downplayed expectations that there would be a breakthrough between both sides in the short term.
"On most of the issues [vice president Šefcovic] believes they can conclude them on a technical level but obviously there are certain political things that are outstanding," said a source present at Mr Šefcovic's briefing to the Conference of Presidents.
A UK government spokesperson said: "Technical engagement with the EU in relation to the protocol has continued over recent days and we remain in regular contact at all levels. The discussions have been constructive but there are still significant differences that need to be resolved.
"Both the UK and EU are engaging with business, civil society and other stakeholders in NI, to understand the issues they are facing.
"The UK remains committed to working through the outstanding issues in order to restore confidence on the ground in Northern Ireland, reflect the needs of communities and respect all dimensions of the Belfast Good Friday Agreement."
Meanwhile, two European Parliament committees are expected to vote this week to give their consent to the EU-UK free trade agreement, concluded in December.
However, the Conference of Presidents has deferred a decision on when the Trade and Cooperation Agreement (TCA) should face a consent vote by the parliament as a whole.
The next plenary session of the European Parliament will take place on 26-29 April.
The Conference of Presidents will decide next Thursday whether or not to put the parliament's consent vote on the agenda of that plenary session.
The TCA is currently being applied provisionally, and cannot be fully ratified until the European Parliament gives its consent.
A plenary vote on consent has been held up due to concerns by MEPs over the UK's move to unilaterally interpret the protocol.