Celtic and Rangers fans swarmed onto the pitch and hurled flares in ugly clashes at Ibrox stadium on Sunday after the latest “Old Firm” derby between Scotland’s biggest rivals.

Celtic won the Scottish Cup quarter-final 4-2 in a penalty shootout after the game ended in a goalless stalemate during regular time in front of 50,000 spectators in a cauldron-like atmosphere at Rangers’ stadium in the city of Glasgow.

With objects being thrown between fans, some of whom masked their faces, police and stewards formed a barrier between the two groups to regain order as players hurried off the field.

Chief Superintendent Kate Stephen, in a statement on the Scotland Police official website, condemned the “shameful” incident, adding that several people were arrested.

“Officers and members of the public have been injured in this despicable display and I want to express my thanks to all officers and staff deployed,” Stephen said.

“A number of arrests have already been made, and Police Scotland will now work with both clubs and the Scottish Football Association to carry out a robust investigation following the scenes on the pitch at the conclusion of the match.”

The Scottish Football Association condemned the behaviour and promised an investigation.

For the first time in eight years, Celtic had been given a full allocation of 7,500 tickets for away fans.

The Glasgow derby is one of the oldest and most intense in world football, dating back to 1888. The rivalry has been fuelled by political and religious divisions.