Republic of Ireland boss Martin O'Neill has admitted that he is "very concerned" about the threat of "exceptional" Zlatan Ibrahimovic when his team take on Sweden in the group stages of Euro 2016.

The Boys in Green will open their campaign against Sweden in Paris on June 13, before also taking on Belgium and Italy in what is one of the toughest sections of the competition.

Ahead of their opener in the French capital, O'Neill has paid tribute to the quality of Ibrahimovic, who is reportedly close to signing a one-year contract with Manchester United.

"[They are a] good side, it will be a difficult game for us but we just have to be ready for it now next Monday. Naturally we will have to be very concerned of Ibrahimovic. He's a top-class player, one of the best in Europe and just an exceptional talent," O'Neill told reporters.

"We will have to be carefully matched, we will have to watch him and try match up against him but I'm not so sure about someone man-marking him."

Republic of Ireland lost 2-1 at home to Belarus in their last international fixture on May 31.