South Korea boss Hwang Seon-hong has claimed Celtic, Brentford and Stoke City all went back on a 'promise' to release players for a key tournament this month after bitter repercussions for their failure to reach their tenth Olympic football tournament in a row.

Celtic blocked winger Yang Hyun-jun from playing because the tournament wasn't in the FIFA calendar and they were under no obligation to release players. They were joined by Brentford and Stoke, although Fortuna Dusseldorf released one of their players,

Hwang - who is the interim manager of his country as well as their Under 23s boss - has come under fire after they were eliminated on penalties by minnows Indonesia in the quarter-finals of the Asian Under 23s Cup.

With the top three teams in the tournament guaranteed Olympic qualification, it means that South Kora missed out on the Paris event - the first time they have failed to qualify since 1988.

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And while Hwang took responsibility, he cited Celtic, Brentford and Stoke's failure to release players as a major reason for their poor performances.

He said: "Firstly, I am the coach and I take full responsibility.

"However, there were circumstances beyond our control such as the failure of some European clubs to release players.

"I personally visited Celtic, Brentford and Stoke City and I was promised the participation of Yang Hyun-jun, Kim Ji-soo and Bae Jun-ho.

"But when the tournament came, the clubs all refused to release their players because all were at a crucial stage at the end of their season.

"What could I do? I visited all of them.

"But yes, there was a lack of preparation for Plan B and Plan C in case the European players failed to join up.”