Gerry Adams walked away from an event at the White House last night, after he faced 90 minutes of extra security checks.

The Sinn Fein President had been invited to the exchange of the shamrock ceremony, but was told there was an issue with "security".

Deputy Sinn Fein leader Mary Lou McDonald and Northern Ireland Deputy First Minister Martin McGuinness both attended the White House celebrations.

In a statement he has described the situation as "unacceptable".

“After two decades of travelling back and forth to the USA and countless meetings in the White House with successive US Presidents, this is an unacceptable development...

...Sinn Fein will not sit at the back of the bus for anyone. We are elected to represent citizens and we will do this. I am hopeful that the controversy around my White House invitation will help lead to a resolution of all these matters.”