'Security breach' reported during Biden’s Belfast visit after sensitive document found on street

Police in Northern Ireland have confirmed a security breach centered around President Joe Biden's visit to Belfast.
According to Telegraph, the president arrived at the Belfast International Airport on Tuesday, April 11, by way of Air Force One.
As Biden is scheduled to deliver a speech at Ulster University Campus in Belfast, BBC's Nolan Show reported details about a document connected to the visit.
The document, found on the street, was marked "PSNI (Police Service of Northern Ireland) and sensitive," the news outlet reported.
Per BBC:
The document, found by a member of the public, allegedly showed a detailed itinerary of Joe Biden's trip, as well as the names of all the officers involved in Biden’s security operation, and the numbers and addresses of top PSNI officers.
A PSNI spokesman said, via Belfast Live: "We are aware of a security breach. An investigation has commenced and we have notified the Senior Information Risk Officer."
"We take the safety of visiting dignitaries, members of the public and our officers and staff extremely seriously and will put the appropriate actions in place," the spokesman added.
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BBC reports an increased presence of law enforcement in the vicinity where Biden is expected to speak. The president is slated to speak about the 25th anniversary of the Good Friday Agreement and the United States' efforts to support Northern Ireland’s economic growth.