Several British ministers are threatening to quit over concessions Prime Minister Theresa May is preparing to make to the European Union on Brexit, UK newspapers said on Friday.

They also come with threats by May's Northern Irish allies to withdraw their support and force her to face a potential confidence motion that could lead to early elections.

British papers said at least two or three ministers could quit over May's concessions on terms for keeping the Irish border open after Britain leaves the EU on March 29.