Gerry Adams, the leader of the left-wing Irish political party Sinn Fein, got a rude reception in leaving Washington on Thursday, with added security screenings before boarding his flight back to Ireland.

Adams was in Washington leading up to the St. Patrick's Day holiday, visiting the State Department and making the rounds at Irish-American events before jetting back to Dublin for more celebration.

While at Dulles International Airport, outside of Washington, he tweeted a picture of his airline ticket with an "SSSS" code, which stands for secondary security screens.

"The dreaded SSSS aris [again]," Adams tweeted with a photo of the ticket.

Meanwhile, the Irish Prime Minister Enda Kenny gave a pro-immigration speech at the White House with President Trump standing at his side. The U.K. Metro website featured the headline: "Irish PM trolls Donald Trump on immigration right in front of him."

Kenny said: "It's fitting that we gather here each year to celebrate St Patrick and his legacy. He too, of course, was an immigrant – and though he is of course the patron saint of Ireland, for many people around the globe he's also a symbol of, indeed the patron of, immigrants."

Adams' party, Sinn Fein, has been called the political arm of the Irish Republican Army. The group had been on the U.S.'s list of terrorist organizations, until he guaranteed a ceasefire in the late 1990s. The "Real IRA," an unaffiliated group, remains on the list.

He was in Washington making the rounds at Irish-American gatherings, asking for those with Irish heritage to support a one-Ireland policy, or unification, in the wake of the United Kingdom's decision to leave the European Union, known as Brexit.

If Ireland is not unified when the U.K. exits, according the Adams, it would shatter the Good Friday Agreement that ended hostilities between Ireland and the U.K. government in England.

"These changing times present real challenges and real opportunities," he said in Washington. "We need to continue to strategise, organise, and persuade for Irish Unity. We need to plan for a United Ireland. There is no short cut. Irish America has a real and crucial role in this transition."

Adams was a key figure in securing the Good Friday Agreement between the Irish Republic, Northern Ireland and England, which ended decades of hostility and ultimately disarmed paramilitary groups like the IRA.