The EU's chief Brexit negotiator on Friday said a lack of consensus on how to maintain a soft border between the Republic of Ireland and Northern Ireland could torpedo any future deal between the entities.Speaking to France Inter radio, Michel Barnier did not rule out the possibility of a hard Brexit, whereby the UK crashes out of the EU without a deal."In my opinion, there needs to be a deal. I'm not sure that we will reach one, it's difficult and possible," the French politician said. Asked whether the deadlock on the Irish border could lead to the collapse of the Brexit negotiations, Barnier said: "My answer is yes." The Irish border was not only a technical issue but also a political one, Barnier added. The 499-kilometre border between the Irish Republic, an EU member state, and Northern Ireland, a UK territory, is currently soft, a status enshrined by a 1998 international peace deal that brought an end to the civil conflict in the region.This means people and goods can cross back and forth across the frontier freely and thousands do so on a daily basis for work or to visit family. Negotiators on both sides of the discussion table have agreed that the border must remain open but once the UK withdraws from the EU, products would default to tariff and customs checks. The EU has asked the UK to provide a backstop -- a kind of insurance clause -- in its Brexit plan to ensure a soft border even in the event of no deal, but Brussels' suggestion that Northern Ireland maintains customs alignment with its southern neighbour have been rejected by London. Both parties were analyzing a proposal to extend the planned two-year Brexit transition period to ensure a deal on the border.