Northern Ireland's DUP leader Arlene Foster speaks to the media outside Stormont Parliament Building in Belfast, Northern Ireland February 6, 2019. REUTERS/Clodagh Kilcoyne

BRUSSELS (Reuters) - Finding a solution for the Irish border after Britain leaves the European Union remains a critical issue for Northern Ireland’s Democratic Unionist Party, its leader said on Thursday after meeting the EU’s Brexit negotiator in Brussels.

“I hope the prime minister takes the time to look at the alternative arrangements to the backstop because the backstop is the critical issue,” Democratic Unionist Party leader Arlene Foster told reporters outside the European Commission, hours after EU leaders extended Britain’s Brexit deadline.

“We believe that she needs to look at that again and she should come out here very strongly and say that the backstop is the issue,” Foster said, referring to British Prime Minister Theresa May.