Play was stopped shortly before the half-hour mark after a section of travelling supporters tore out plastic seats and launched them toward police and stewards stationed at the front of the stand. Officers responded by forming a protective line, while match officials ordered the players to move away from the touchline.

Young Boys captain Loris Benito made his way over to the away section in an attempt to calm supporters as stadium announcements warned the match could be abandoned if disorder continued.

Several officers were seen shielding themselves from flying objects, though no serious injuries have yet been reported.

UEFA is expected to open an immediate investigation, with sanctions for the Swiss club likely.

The game resumed after a brief stoppage, but the atmosphere remained tense, with both clubs urged by match delegates to maintain communication with supporters.