Scotland's First Minister Nicola Sturgeon has condemned the Rangers supporters who marred Sunday's Glasgow derby defeat by Celtic at Ibrox with their "mindless, thuggish behaviour".

The start of the second half was delayed when Celtic goalkeeper Joe Hart pointed out shards of broken glass in his goalmouth after a bottle was thrown on to the pitch, while other objects rained down when visiting player Jota was taking a corner kick.

A member of Celtic's backroom staff later required stitches after being struck in the head while making his way towards the tunnel as the visitors won the match 2-1 to move six points clear of Rangers at the top of the cinch Premiership with six games to play.

Sturgeon labelled the actions of those responsible as "unacceptable".

"This sort of behaviour is not acceptable," the First Minister told LBC on Monday morning.

"Whether it happens at a football match or in the street, people throwing glass bottles is just not acceptable.

"It’s mindless, thuggish behaviour and it has no place in any civilised society.

"But these are matters for the authorities, obviously for the football authorities and potentially for the police and criminal justice authorities.

Some of the glass bottles left behind after the match yesterday

"Regardless of what team you support, I’m not the world’s biggest football fan and not just because my team is Ayr United, but people should be able to enjoy football.

"Football should be something that people can take their kids to and have a happy, joyful occasion.

"Behaviour like that whether it's at an Old Firm match or any other football match besmirches that, and it should absolutely be seen as unacceptable."

Rangers Supporters Liaison Officer Greg Marshall has called for help to identify the person responsible for the shattered glass in Hart’s goalmouth.

He tweeted on Monday afternoon: "We are working with Police Scotland to identify the individual who threw a bottle onto the pitch at half time yesterday. This delayed the start of the second half and put players safety in danger. Anyone with information can pass details anonymously to either the club or Police."

Police investigations are ongoing.