Two high-profile Sinn Féin representatives have been denied entry to the US, amid mounting speculation that the ban on party members fundraising in the country could be lifted next month.
Conor Murphy MP and assembly member Barry McElduff had been due to travel to Boston earlier this week for a series of meetings and to take part in a number of events including a 1981 Hunger Strike commemoration.
However they were forced to cancel the trip after their visas were refused.
Mr Murphy, who is also assembly member for Newry and South Armagh, said he had been told the applications were declined because they were unable to be processed in time.
"I accept this explanation and I do not believe that anything political lies behind this decision," he said.
"While I am disappointed not be able to fulfil this commitment, the events will go ahead as planned and a number of other Sinn Féin representatives, including assembly member Davy Hyland, have travelled to Boston to take part in the planned programme."
A US spokesman said: "Due to privacy laws the consulate does not comment on individual visa applications."
It is understood Mr Murphy and Mr McElduff had planned to attend a photography exhibition on the 1981 Hunger Strike and events surrounding the Ulster championship hurling final between Antrim and New York.
Meanwhile, it has been suggested that the US administration is being pressed to lift the fundraising ban on Sinn Féin before a gala dinner next month in New York due to the positive assessment of the IRA in the most recent report by the Independent Monitoring Commission (IMC).
It is understood party leader Gerry Adams has applied for a visa to travel to the US for the event on November 9.
The ban permits entry to the country for Sinn Féin politicians but refuses them the right to fundraise.
The annual Friends of Sinn Féin (FOSF) dinner at the Sheraton Hotel is one of the most important dates in the Irish American calendar.
Tables at the event can cost up to $5,000 each.
In March FOSF had to refund more than $100,000 to supporters who attended a St Patrick's Day breakfast with the Sinn Féin leader.
However, Mr Adams is not believed to have received a response to his request yet.
The ban was imposed on Sinn Féin members last year in an apparent bid to pressure the party into joining the Policing Board after the murder of Robert McCartney and the Northern Bank robbery.
However, with the IMC's glowing assessment of the IRA as an organisation "now firmly set on a political strategy, eschewing terrorism and other forms of crime", sources believe the ban will be lifted.