CELTIC have threatened to close part of their stadium if fans do not improve their "unsafe" behaviour.

The warning came after Tuesday's Champ­ions League qualifying match against Cliftonville saw the referee ask some supporters to stop launching fireworks.

Celtic confirmed three fireworks exploded within Section 111 – where the 'Green Brigade' supporters' group are situated – and warned fans over their future conduct.

The club said instances of overcrowding, non-compliance with stewards, blocking of aisles, 'moshing' (jumping up and down) and crowd surfing (being lifted over fans) could result in the section being closed.

Officials said they were reacting to "serious safety concerns" raised by the Glasgow City Council Safety Advisory Group.

The club's warning came as it was revealed Uefa, the European ruling body, has started disciplinary proceedings against Celtic over the lighting of fireworks against Cliftonville.

Neil Lennon's side won the match on Tuesday 2-0, to secure a 5-0 win on aggregate.

The case will be discussed by UEFA on August 22.

In a statement, Celtic said: "The club's position was to close Section 111.

"But following discussions between the club's supporters' liaison officer and representatives of the 'Green Brigade' that decision has been reviewed and the section will remain open.

"However, the situation will be monitored at the Celtic FC v Borussia Monchengladbach match on July 27, and v IF Elfsborg on July 31."

A council spokesman, said: "We will continue to work with the club to ensure spectator safety within the stadium."

rebecca.gray@ eveningtimes.co.uk