Celtic manager Neil Lennon has been hit by a spectator during a Scottish Premier League game against Hearts at Tynecastle in Edinburgh.
The incident occurred after Celtic's Gary Hooper had put the visitors two goals ahead.
Before the game could restart a fan clambered from the Hearts section of the main stand and made for the Celtic boss who was on the touchline.
He connected with the Celtic boss before being bundled to the ground.
After a brief fracas, police and stewards handcuffed the fan and took him away.
Scottish Football Association chief executive Stewart Regan issued a statement, saying: "Clearly this kind of behaviour from supporters is wholly unacceptable.
"The safety of players, club officials and match officials is paramount on or around the field of play, and this clear breach of security is a matter I will be discussing with SPL chief executive Neil Doncaster tomorrow."
Celtic won the game 3-0 to ensure the SPL title race goes to the final day.
The incident occurred after their second goal in the 49th minute.
The Celtic manager looked stunned after the attack but was uninjured.
Former Northern Ireland boss Lennon has been in the headlines regularly this season.
In January a package addressed to him containing bullets was intercepted at a sorting office in Country Antrim.
In March, the club confirmed Lennon was under 24-hour security surveillance after a suspicious package was intercepted at a Royal Mail sorting office in Saltcoats, Ayrshire.
On 19 April it emerged that Royal Mail intercepted a total of two "viable" parcel bombs addressed to Lennon.
http://www.bbc.co.uk/news/uk-scotland-13368945