The US Secret Service apologized to Sinn Féin President Gerry Adams yesterday for denying him entry to the annual official St. Patrick’s Day celebration at the White House. The story was first reported by Irish Central.

A spokesman for the Secret Service, Robert K.Hobak, apologized during an interview with The New York Times saying it was an unfortunate administrative error.

Sinn Fein personnel however suspected there were other forces involved in blocking Adams entering the White House which he  has visited 22 times. Leaders in Congress penned an angry letter to White House Chief of Staff Denis McDonough over the incident.

Adams had earlier declared the delays in allowing him into Tuesday’s St. Patrick’s Day celebrations as an “unacceptable development.”

The Irish political leader commented on the events of Tuesday evening which saw him left waiting for 90 minutes, awaiting entry into the annual event hosted by President Obama. In an official statement on Sinn Féin's website Adams voiced his disappointment in the manner in which he was treated by White House staff.

“I had received my usual invitation to attend the St. Patrick’s Day celebrations in the White House and was pleased to accept,” Adams said.

“When I arrived the staff at the White House informed me that there was an issue of ‘security.’

“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.”

The US Security Service has since apologized for the delays, stating that an administrative error caused the issue.

“The Secret Service would like to express our regret that the issue involving Mr Gerry Adams’ entry into the St. Patrick’s Day reception could not be resolved in a more timely manner,” a spokesperson said.

“Unfortunately, an administrative input error received by the Secret Service was not able to be rectified promptly.”

Adams' exclusion from the event left many Irish American leaders baffled. Members of the Friends of Ireland caucus in the House of Representatives addressed a letter to Chief of Staff Denis McDonough expressing their outrage that Adams was denied entry to the reception.

Signed by members of congress including Richard E. Neal, Peter King, Brendan Boyle, Joe Crowley, and James P. McGovern, the letter stated: “For more than three decades, the United States government has continuously encouraged the political parties in Northern Ireland to take risks for peace. But instead of being rewarded for their efforts, many members of Sinn Fein are now being punished. This unfortunate behavior seems to be happening with increasing regularity.”

Irish-American Democratic congressman Brendan Boyle, who also signed the letter, told The Irish Times that the incident was greatly discussed when the Friends of Ireland caucus met with Adams on Wednesday morning.

“A group of us were anywhere from annoyed about it to pretty angry about it, and we intend to raise it with the White House,” he said.

Boyle believed that the delay was either “a very embarrassing bureaucratic snafu or is there something more sinister going on.”

The official letter from the Friends of Ireland reinforced this belief that Sinn Féin politicians, in particular, are being isolated because of their political affiliations.

“After years of conflict, Northern Ireland is now seen as a society in transformation, and the negotiations that led to the power sharing institutions in Belfast are now seen as a model of successful conflict resolution across the globe,” the letter continued.

“Despite this progress, representatives of Sinn Féin continue to experience extraordinary difficulties when travelling to the United States, and we believe that many of these individuals are being victimized because of their party affiliation. While raised with administration officials repeatedly, the situation is going from bad to worse.”

“He [Adams] was invited to his [Obama’s] home and all of a sudden was excluded and frankly I can’t understand it,” commented celebrated Irish American lawyer and lobbyist for immigration rights, Brian O’Dwyer.

“I’m outraged in a sense that Gerry Adams has for years and years worked diligently for peace in Northern Ireland and the intentionality of reversing the hard work a number of Irish Americans have put into the peace process in terms of ensuring that all parties were welcomed and play a part in the process so that a process that's always fragile could be sustained, can only be described as an intense act of incompetence.”

Adams, a newly re-elected TD for County Louth, planned to attend the annual presentation of the shamrock to the US President in Washington D.C., held two days early this year on March 15 as caretaker Taoiseach Enda Kenny must attend a meeting in Brussels on March 17, along with North Ireland Deputy First Minister Martin McGuinness and Sinn Féin Vice-President Mary-Lou McDonald, both of whom were allowed into the event.

Some pics from yesterday's engagements with @POTUS at the White House & Speaker's lunch on Capitol Hill.

— Martin McGuinness (@M_McGuinness_SF) March 16, 2016

Adams, however, was halted as he tried to gain entry and forced to wait for almost an hour and a half because of apparent security concerns. Whereas McGuinness and McDonald continued into the party, Adams was asked to step aside by security personnel as they inspected his documents.

On hearing that Obama had begun to speak at the event, Adams made the decision to wait no longer and left.

The Sinn Féin President stated yesterday he believes the refusal to allow him entry to one of the most important events in the Irish calendar in the US was an attempt to set Sinn Féin aside from other Irish political parties.

“It is obvious that there remain some within the US administration who seek to treat Sinn Féin differently,” he said.

“Some of our political representatives have been denied access to the USA while others, including myself, have to regularly go through additional searches and scrutiny when we travel to and from the USA.”

Irish American lawyer Brian O’Dwyer also believes that the slight showed a lack of respect for Adams. “It makes no sense. I can't understand. He’s the leader of an Irish political party and it’s insulting,” he said.

“Obviously somebody needs to apologize. If someone was invited into my home and was treated that way I would pick up the phone and apologize to them.

“He’s a politician and the leader of the second largest party in Northern Ireland and the third largest party in the South and deserves to be treated with great respect.”

Adams yesterday tweeted images of his White House invitation and the letter confirming his attendance before releasing his official statement.

My invite 2
The White House. Just saying.

— Gerry Adams (@GerryAdamsSF) March 16, 2016

Confirmation of my invite 2 White House Reception. From the White House.

— Gerry Adams (@GerryAdamsSF) March 16, 2016

He also stated that the refusal tactic had been previously used in the US in an attempt to influence Sinn Féin, in particular, during the Stormont crisis last year when the State Department initially refused to meet with him.

“Last year the State Department initially refused to meet me as part of a transparent effort to pressurise Sinn Féin during negotiations at Stormont,” Adams continued.

“That meeting did take place after protests from US political leaders. Efforts to pressurise us in the negotiations failed.”

Congressman Boyle also agrees that the State Department has become harsher in recent years in their dealings with the Sinn Féin leader.

“It is odd that here is this wonderful event – very inclusive, everyone’s welcome, a chance to celebrate everything that’s been achieved over the last two decades,” he told The Irish Times, “and now you are going to have Gerry Adams who is invited as a guest, to stand outside for an hour and a half because security won’t let him in. It’s embarrassing.”

Adams has not met with any further delays in the US following Tuesday evening. On Tuesday morning he attended a lunch with Speaker Paul Ryan, following an appearance at the Brehon Law Society Dinner in New York on Monday evening.

Cold wet day in New York. Gerry speaking 2 Brehon Law Society 2nite. Praising their efforts for justice & equality.

— Richard G McAuley (@richardgmcauley) March 15, 2016

Adams said: “This morning [Wednesday, March 16] Martin McGuinness, Mary Lou McDonald and I met with the Congressional Friends of Ireland. They too shared our grave disappointment at the White House situation and expressed their determination to have this issue resolved.

Sinn Fein will not sit at the back of the bus for anyone,” he concluded. “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.”

Enjoying his last St. Patrick’s Day in office, Obama once again referenced his own Irish heritage in his St. Patrick’s Day address.

“This, of course, is one of my favorite events,” Obama said. “I get to welcome my people and the Obamas of Leinster are nothing if not welcoming.”

“Of course, for the Irish, home is everywhere and nowhere in the world is more everywhere than the United States. We are braided together in so many ways, America and Ireland.

“We have been for centuries, through history, through bloodline. We’ve waged war side by side, we’ve waged peace side by side.

“We are family and we are friends.”