BRUSSELS (AP) — European Commission President Jean-Claude Juncker will use his first day back at work after a gallbladder operation to speak to British Prime Minister Boris Johnson by phone about stalled Brexit negotiations.

Juncker's spokeswoman Mina Andreeva said Tuesday it was up to Britain to come up with concrete proposals to break the deadlock over the how the EU-UK border on the island of Ireland would be managed once both sides split up.

With a target departure date of Oct. 31 drawing nearer, Andreeva said any proposal by Johnson would need to be "compatible with the withdrawal agreement" that the EU negotiated with his predecessor Theresa May. Johnson is insisting that the Irish border arrangement in the agreement must be changed, something the EU has steadfastly refused.