A post-Brexit "hard" border between Northern Ireland and the Republic of Ireland must not be allowed to happen, political leaders have warned at a summit in Cardiff today.
First Minister Carwyn Jones also insisted Wales must not get a bad deal in the Brexit negotiations.
He was speaking at an extraordinary meeting of the British-Irish Council.
Watch: Owain Phillips reports:
People and goods going between the two nations have been able to move freely thanks to the Common Travel Area (CTA). The open borders agreement, set up in the 1920s, has been strengthened by both Britain and Ireland's European membership.
However, questions and concerns have been raised about what this means for the CTA and for both economies in the wake of the UK's Leave referendum result.
The issue was one of the hot topics discussed at an emergency meeting of the British Irish Council in Cardiff - which was called by Wales' First Minister Carwyn Jones.
Watch: Wales' First Minister speaks to ITV Cymru Wales about Brexit:
Among heads of government attending the talks were Ireland's Taoiseach Enda Kenny, Scotland First Minister Nicola Sturgeon as well as Northern Ireland political heavyweights Arlene Foster and Martin McGuinness.