EU chief Brexit negotiator Michel Barnier (L), and David Frost, UK chief negotiator. (Photo: Getty images/VNA)

The negotiating teams will meet in Brussels until Thursday, focusing on fair competition, fisheries, services, energy, and judicial cooperation.  

The two sides are striving to reach an agreement by the end of October, the last date that would allow the agreement to be ratified in time to enter into force on January 1, 2021.