An investigation is under way after a riot at an African Champions League tie described as “apocalyptic” by one of the teams involved.

The violence led to a 40-minute delay to the second half, with Kabylie revealing they asked for the game at the Rades Stadium to be abandoned before being told to return to the pitch by officials.

The game eventually ended in a 1-1 draw, giving Esperance a 2-1 aggregate victory.

The four-time African champions could now be forced to play future games in the competition behind closed doors if tournament organisers the Confederation of African Football (Caf) follow precedent, having imposed a similar sanction on the club following violence in a match against Tunisian rivals Etoile Sportive Sahel last season.

After trouble also flared at one of the weekend’s other quarter-finals, the tie between Raja Casablanca and Al Ahly, Caf released its own statement condemning both incidents as “unacceptable”.

What happened and why a chainsaw?

Having been sanctioned last season, Esperance officials and fan representatives have been working together to ensure order at home games and the first half against Kabylie had passed off without incident.

When trouble did flare, those involved appear to have targeted a storeroom under the stand where maintenance equipment, including the chainsaw, was being kept.

Footage circulating on social media shows a man with a black scarf around the lower part of his face carrying the chainsaw among the wreckage of broken fencing while other men start a fire.

Esperance fan Walid, who has attended all of the club’s home games in the Champions league this season, told the BBC the violence was “very unusual” and could not say what started it.

He went on to describe what happened as “chaotic” and like being in “a warzone”, as spectators fought with riot police and firefighters were called in.

Visiting the scene in the aftermath, Tunisia’s interior minister, Kamal El-Feki, announced the investigation, promising to punish those involved.

Esperance supporters who were not involved, and who are angry about what happened, are also trying to track down offenders, sharing images online, including one of a man holding the chainsaw later in the game.

Speaking to local radio station Diwan FM, a court spokesman said more than 60 arrests had been made, including 12 minors.

‘The hell of Rades’

While Esperance are yet to comment, Kabylie released a statement addressing what the club called “the hell of Rades”.

Labelling events as “apocalyptic”, the two-time African champions described “projectiles and fireworks of all kinds that flooded the field, crimes by local supporters and the use of tear gas by local security that made the atmosphere unbreathable”.

Due to concerns about the safety of players, staff and supporters, Kabylie say they tried unsuccessfully to persuade match officials to call off the game during the elongated half-time break, but claim to have been threatened with sanctions if they did not return to the field of play, having been told the “situation was under control”.

The Algerian side, who are based in Tizi Ouzou, are believed to have submitted their own report to Caf.

While their statement mentions “assaults, injured supporters”, authorities in Tunisia are yet to release details on how many people may have been hurt.

Esperance now face Egypt’s Al Ahly in the semi-finals with the first leg in Tunis on 12 May.