Britain and the EU did not reach "complete agreement" on Brexit divorce terms during talks in Brussels on Monday but should be able to later this week, European Commission President Jean-Claude Juncker said.

"Despite our best efforts and the significant progress we and our teams have made in the past days on the remaining withdrawal issues, it was not possible to reach a complete agreement today," Juncker told reporters after meeting May on what the EU had said was the "absolute deadline" for an improved offer from London.