Irish army bomb experts made safe a crude but viable explosive device found at an office building in central Dublin on Friday, close to where world leaders had dined the night before during a two-day summit in the Irish capital.

Irish police said they responded to a report of a suspicious device on Friday afternoon in a building on Merrion Square. Leaders from the European Political Community, which includes European Union and non-EU countries, had met for dinner at a venue on another side of the square on Thursday.

"Based on initial Garda assessment the defence forces Explosive Ordnance Disposal (EOD) team were requested to attend the scene. The EOD team has made what is a crude but viable device safe," police said in a statement.

French President Emmanuel Macron, British Prime Minister Andy Burnham and Canadian Prime Minister Mark Carney, a guest at the event, attended the dinner at the National Gallery of Ireland. Ukrainian President Volodymyr Zelenskyy was also at the summit but did not attend the dinner, as he was meeting U.S. presidential envoys Jared Kushner and Steve Witkoff on the outskirts of Dublin.

A security cordon was placed around the dinner venue, with roads in the vicinity of Merrion Square closed off. Police said the two-day gathering was the largest security operation they had ever undertaken. The summit continued on Friday with an informal meeting of European Union leaders at a separate venue 1.5 kilometres from where the device was discovered.

An investigation is under way, police said. The statement did not say when police believe the bomb was planted or give other details about it.