Michel, speaking in Dublin after talks with Irish Prime Minister Micheal Martin, urged Britain to put its cards on the table, saying the bloc needed clarity about their position.
“The coming days are crucial. This is the moment of truth. There is only one week to go before the European Council meeting on 15-16 October," Michel told journalists.
“This is a challenging situation. We think we need more clarity and we will see if it is possible to make real and concrete progress,” he said.
The two sides say they are inching towards a deal that would govern around $900 billion in trade after 31 December - when the current transitional arrangements end - though sticking points remain on fishing, level playing field issues and governance.
Martin said the mood around the talks had changed in recent weeks, leading to intensified engagement between the two sides.
The United Kingdom formally left the EU on 31 January, more than three years after it voted 52%-48% for Brexit in a 2016 referendum. The two sides are now trying to work out how everything from cars to Camembert to whisky will trade.
