Northern Ireland manager Michael O'Neill has called Oliver Norwood's decision to retire from international football "premature" and "a huge mistake".

The 28-year-old midfielder made the announcement on Monday, wanting to concentrate on his club career with Sheffield United – who are back in the Premier League after a 12-year absence and won their first game of the season against Crystal Palace on Sunday.

Norwood, who was born in Burnley but qualified to play for Northern Ireland through his grandfather, won 57 caps for his country and also represented them at under-19 and under-21 level.

"I think he is making a huge mistake. He is only 28 and I've no doubt he could have continued to play club and international football for many years," O'Neill told irishfa.com.

"Ollie has been a mainstay of our team for the past seven years. I know this was not an easy decision for Ollie to make, however I think his decision is premature.

"He had the opportunity to leave an incredible legacy at international level and the potential to reach 100 caps.

"Ollie will be a loss to our squad, however we have won our four qualifying games to date (for Euro 2020) in his absence and the squad will continue to progress, and I believe the players in my squad are more than capable of reaching another major tournament."

Norwood, who came through the ranks at Manchester United, was handed his international debut by former manager Nigel Worthington, coming on as a substitute in a 2-0 friendly defeat to Montenegro in Podgorica in August 2010.

Fifty-two of his 57 caps for Northern Ireland came under current boss O'Neill.

"After proudly representing Northern Ireland on 57 occasions, I feel now is the right time to announce my retirement from international football," Norwood said in a statement released via his club.

"I've enjoyed the highs of a major tournament – being part of the squad in France at Euro 2016 was the proudest point of my international career.

"I would like to thank the manager, Michael O'Neill, for selecting me on so many occasions to represent my country, and also to the players I've played with through the years. We've had some enjoyable times.

"A huge thank you, too, to the GAWA (Green and White Army) for the tremendous support offered through the years. In my opinion the GAWA really are the best fans in the world and hopefully the squad can deliver more success for them to enjoy."