Prime Minister Theresa May has said Britain will play a "full and active role in the EU" until it leaves.
Following Brexit, Britain will remain "open" and "outward looking" and is committed to trading freely with other European countries, she said.
The prime minister is attending her first EU summit following the referendum.
The premier of Belgium's Wallonia region Paul Magnette has told his region's parliament that no breakthrough has been made in talks over the planned EU-Canada free trade deal.
Although all 28 EU governments support the Comprehensive Economic and Trade Agreement (CETA), Belgium's French-speaking Wallonia region opposes it, meaning the country as a whole cannot give assent.
Wallonia maintains that CETA poses a threat to farmers and to welfare standards.
Mr Magnette said talks on Friday had yielded some developments, but pointed out that contention still remains over an independent court system to resolve disputes.
Critics say the court system can be exploited by big business to unduly influence public policy.
CETA is expected to take centre stage is the EU leaders' summit, which is currently underway in Brussels.
Asked if she was undermining the UK position, she said: "You can't undermine something that doesn't exist."
The deal would set up a free trade zone between the EU and Canada - and could be an important test for the UK's Brexit negotiations.
European Commission President said an EU-Canada free trade deal would help end Canadian visa restrictions for Romanians and Bulgarians.