Talks between the EU and the UK on a Brexit trade deal are expected to continue until the end of the week.
Ursula von der Leyen and Boris Johnson agreed the negotiations should continue in a phone call.
It came as British supermarkets said they were laying in extra stock - and asked shoppers not to panic-buy.
The EU's chief negotiator has told member states they are considering a short extension to the transition period.
Sources in Brussels are saying there has been some progress in negotiations in the past few days but substantial gaps still need to be bridged.