The European Union (EU) has warned that incoming UK Prime Minister Boris Johnson faces challenging times as it reacted to his election as new Conservative leader.
Mr. Johnson has the immediate task of guiding the UK out of the EU ahead of the October 31 deadline.
He wants to renegotiate an agreement with the EU, ditching large parts of the deal outgoing Prime Minister Theresa May struck last year.
But EU leaders have said the withdrawal agreement is not up for renegotiation.
The European Commission's newly elected President, Ursula von der Leyen, has however said she is willing to grant the UK another extension to Brexit talks, if London comes up with good reasons.