LONDON (Reuters) – The Northern Irish party that props up British Prime Minister Theresa May’s minority government warned on Thursday against giving too many concessions in Brexit talks on the future border arrangements with Ireland, Sky News said.

Sky’s political correspondent, Faisal Islam, cited unidentified sources as saying that the Democratic Unionist Party had met the government this morning.

Sky said the DUP warned that any British commitment on Northern Ireland staying in the single market, customs union or regulatory equivalent “would be deeply destabilising” for the deal they struck earlier this year to keep May in power.