Celtic have been hit with two more UEFA charges - one for their fans' behaviour and another for their team's.
Celtic again face a charge relating to supporters letting off fireworks, days after being fined for an identical offence.
But the players have also got the club into trouble after being accused of "improper conduct" during their 1-0 Europa League defeat by Inter Milan.
The improper conduct charge is sparked by a team that receives five or more cards during a game.
Ronny Deila's team had Virgil van Dijk sent off following two bookable offences in the first half of their defeat, which saw them lose 4-3 on aggregate, and a further five players booked.
Deila criticised referee Ivan Kruzliak for his decision to send off the Dutch defender while skipper Scott Brown felt the Slovakian referee had been too harsh throughout.
Brown, who was not booked, said: ''Football is a man's game there's always going to be tackles that are a wee bit late due to the pace of the game. These things happen but every single tackle shouldn't be a yellow card.''
Celtic had appealed for fans to behave at the San Siro after being fined 10,000 euros (approximately £7,300) on Wednesday after a supporter let off a flare during their group match against Dynamo Zagreb in Croatia.
But pyrotechnics were evident in the visiting section in Milan and both clubs have received the same charge.
It is the seventh time in little over three years that Celtic have faced UEFA punishment because of incidents involving fans.
UEFA's control, ethics and disciplinary body will consider the charges on March 19.
Celtic appealed for help in rooting out those responsible for the flares after being "inundated" with messages from angry fans.
A statement read: "Over 3,000 fans travelled to Milan and once again supported the club brilliantly. Everyone at Celtic thanks these fans sincerely for the magnificent support they gave the team on another European occasion.
"It is important to note that Inter Milan and the local Italian authorities have also applauded our fans for their excellent conduct and positive support.
"Unfortunately, one or two individuals have again damaged the club they claim to support, resulting in a further UEFA charge for the use of flares.
"Today we have been inundated with support from Celtic fans who want an end to this activity and, like the club, do not want those responsible associated with Celtic in any way.
"We would urge anyone with information on who these people are to get in touch with the club so that we can deal with this matter and get back to celebrating all that is great about our club."
Celtic also announced they would challenge the improper conduct charge.
A club spokesperson said: "UEFA rules state that they are able to open disciplinary proceedings against any club which receives five or more bookings.
"Celtic can confirm that this is a charge which the club will be contesting."
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