President Donald Trump stirred controversy during a visit to Dublin on Saturday after expressing support for the eventual reunification of the Republic of Ireland and Northern Ireland.

Trump began his visit with a closed-door meeting with Irish President Catherine Connolly before holding talks with Taoiseach Micheál Martin.

Speaking to reporters alongside Martin, Trump said he would “love to see” Ireland unified and described the prospect as a positive development.

“I think it would be a great feather in everybody’s cap if that happened,” Trump said, adding that he believed reunification would eventually take place.

His remarks touched on one of the most sensitive political issues on the island of Ireland and prompted criticism from unionist politicians in Northern Ireland, who stressed that any change to the region’s constitutional status must be determined by its people.

Ireland was partitioned in 1921, creating Northern Ireland, which remained within the United Kingdom, while most of the rest of the island eventually became an independent state.

Decades of political and sectarian conflict followed, culminating in the period known as the Troubles, which began in the late 1960s and lasted for about three decades.

The 1998 Good Friday Agreement largely brought the conflict to an end and established a political framework under which Northern Ireland remains part of the United Kingdom unless a majority of its people vote for constitutional change.

Trump’s comments reopened debate over the politically sensitive question of Irish reunification, with unionist leaders rejecting outside influence over Northern Ireland’s future while some nationalist politicians welcomed renewed discussion of the issue.