RTÉ News has learned that several US Congressman have made representations on behalf of Sinn Féin's Rita O'Hare who has been denied a visa to enter the country.
Ms O'Hare was to accompany Martin McGuiness to the US next week. It is understood that a visa was denied.
The US State Department would not confirm or deny if this was the case, citing confidentiality.
The US Special Representative to Northern Ireland, Mitchell Reiss, took a ten minute call from one senior Irish American Congressman who expressed his disagreement with the decision.
Dr Reiss was in Dublin today for talks with the Taoiseach and met Sinn Féin President, Gerry Adams, earlier in the week.
Martin McGuiness is expected to meet US Congressmen in Washington next Thursday.
