Lack of clarity on the future relationship between the UK and the EU has left the majority of European regions unable to properly assess the potential impact of Brexit, a senior European politician has said.
European committee of the regions president Karl-Heinz Lambertz said the majority of local authorities had yet to formulate firm plans to cope with potential lost trade, tourism and other ties with the UK.
The head of the advisory body for regions across the EU-28 told an Irish parliamentary committee that the regional impact would be felt not only in Ireland and Northern Ireland but also other smaller European countries.
"There will be no winners from this process," Mr Lambertz said.
He said the UK's withdrawal was already affecting Europe's cities and regions.
A delegation of five leaders from across the EU is set to visit the border on Wednesday. They include leaders from Belgium, Finland, Germany and the Netherlands.
Mr Lambertz told an Oireachtas committee on EU affairs that the EU had made considerable efforts to help stabilise the political and social situation in Northern Ireland, and would be most concerned about jeopardising what had been achieved.
"When asked to choose between hard or soft borders, I would go for a 'transparent' one," Mr Lambertz said.
The European committee of regions recently called for an operational solution to be devised in due time to avoid a hard border.
Committee chairman Michael Healy-Rae welcomed the European committee's commitment that the Good Friday Agreement would not to be jeopardised by the Brexit process.
Senator Neale Richmond said it was very hard to help businesses prepare for Brexit when the EU and the UK were in the midst of negotiations.
He said Ireland would be impacted more than any other region in the European Union.
"And the region that will be most impacted will be the border region," the Senate spokesman for EU affairs said.
"Any form of a border, any form, particularly a hard border, will result in a return to violence," he said.
"Not maybe, not could, will."