Sinn Fein vice president Michelle O'Neill is travelling to Washington on Monday to "update" senior US officials on "the current situation" in Northern Ireland following recent election results.
Her party became Northern Ireland's largest in local government in the recent council elections, with the number of first preference votes cast for nationalist candidates also exceeding those for unionist candidates.
This followed last year's Assembly elections, when Sinn Fein also became the largest party for the first time.
