Published Thursday, 12 May 2011
The alleged al-Qaeda sympathiser, who is aged in his 40s, was detained over claims made in a newspaper article.
A Garda spokesman said officers from the Special Detective Unit investigating threats to kill or cause harm searched a home in Dublin's north inner city on Thursday.
The suspect is being held in Store Street Garda station under the provisions of Section 30 Offences Against the State Act 1939 as amended.
Mr Obama is due to visit Dublin and his ancestral home Moneygall, Co Offaly, later this month.
Security surrounding the president has been stepped in recent weeks, due to both the heightened dissident threat in Northern Ireland and the US forces killing of al-Qaeda leader Osama Bin Laden.