Forget the customary open-topped bus, think more an armoured personnel carrier.

That was the vehicle of choice for Red Star Belgrade football players on Tuesday as they celebrated progressing to the Group Stage of the UEFA Champions League.

It kept a military theme going. Prior to the match, Red Star fans had parked a battle tank outside the club's Rajko Mitic Stadium, before the second leg of their play-off with Swiss champions BSC Young Boys.

The tank, a Soviet-made T-55, was used during the bloody break-up of Yugoslavia in the 1990s. It was parked near the stand reserved for Red Star's most ardent supporters, known as "Delije" – which can be roughly translated as "heroes", "hardmen" or "studs" – who in the past have been involved in violent incidents and expressed strong nationalist views.

The stunt triggered outrage from neighbouring Croatia, which fought a war for independence from Serb-led Yugoslavia. Croatian media called it "a clear provocation" and urged European football's governing body UEFA to react.

In Zagreb in 1990, at least 59 fans and 79 policemen were injured as riot police used batons and tear gas to stop violent clashes inspired by nationalist hatred between Serb and Croat fans before a major Yugoslav soccer league match between the city's Dynamo club and Red Star Belgrade.

But Red Star fans say the tank merely symbolises their slogan, "the machine has started", and dozens were seen lining up to have photos taken beside it.

One supporter, Borislav Danilovic, said: "This tank is a nice thing, it's a symbol of the Northern Army, our fan group.

"This is not a provocation. I was watching on TV, Croats are complaining. Croats on Facebook are complaining. Those who don't like us complain, but, for me, it's a great thing."

Serbian authorities have described the tank as a "replica" and said it contains no material that might put the public at risk, while Serbian army officials say the tank was stripped of all its major equipment and is now just a "museum piece".

Defence ministry spokesman Milan Gujanica said: "It does not have an engine, it does not have transmission, the gun on the tank has been welded off, all the shooting and optical devices have been removed."

Red Star fan Nenad [no surname given], said that the war was in the past, while referring to recent reports of ethnically motivated attacks on Serbs in Croatia. "It isn't important anymore, the war ended 25 years ago... it's totally irrelevant. It matters more that they don't beat up the Serbs over there and we don't beat anyone up, right?"

The tank display comes a week after masked assailants attacked two bars in the Croatian towns of Đevrske and Uzdol as ethnic Serbs watched Red Star's first leg-match against Young Boys on television, seriously injuring five people including a nine-year-old. Both towns have a majority Serb population.