Northern Ireland's second-largest pro-British party has voted to quit the province's government amid rising concerns the power-sharing administration could collapse.
The Ulster Unionist Party leadership on Saturday voted unanimously to withdraw from the coalition government with Irish nationalist parties, after claims the Provisional IRA (PIRA) paramilitary group still exists.
"The Ulster Unionist Party will be leaving the Northern Ireland Executive next week," its leader Mike Nesbitt announced after a Saturday meeting.
"This decision was unanimous."
The UUP is too small to cause the administration to collapse by itself, but its decision underlines the fragility of the power-sharing arrangement that helped quell decades of violence in the region.
The larger Democratic Unionist Party has said that Sinn Fein, the main nationalist party and former political wing of the IRA, should be excluded from the government instead of unionist parties leaving, but has warned that it too could quit if Sinn Fein does not address the issue of alleged ongoing IRA violence.
The UUP said that trust in Sinn Fein had been destroyed after police assessments that members of the supposedly defunct group were involved in a recent Belfast murder, and that some Provisional IRA structures still exist.
Sinn Fein leader Gerry Adams has insisted that the IRA has "gone away".
Disarming the paramilitary group was a key part of a 1998 agreement to end conflict between mostly Protestant unionists who believe that Northern Ireland should remain in the United Kingdom, and predominantly Catholic republicans who want the province to be part of Ireland.
The UUP is one of five different parties that make up the power-sharing administration.