BRASILIA, April 28 (Xinhua) -- Brazil's government condemned the behaviour of fans on Sunday after dozens of caxirolas - Brazil's official 2014 World Cup instrument - were thrown onto the pitch during a stadium test event.
An estimated 30,000 fans were handed their own caxirola - a type of plastic maraca - before the local derby between Bahia and Vitoria at the newly opened Fonte Nova stadium.
But the shaker was turned into a projectile by scores of irate Bahia fans as their team trailed 2-0 just before half-time.
Play was interrupted for several minutes as players and officials removed the instruments from the pitch.
"It's not good news," Brazil's sports minister Aldo Rebelo said, before seemingly ruling out the prospect of a caxirola ban.
"It doesn't necessarily mean the same thing is going to happen if Brazil is losing during the World Cup."
Created by musician Carlinhos Brown, the caxirola is made from recycled plastic and comprises a small basket of woven straw filled with dried seeds.
The idea for the instrument was inspired by the success of the vuvuzela at the 2010 World Cup in South Africa.
According to Brown, the caxirola has already been given approval to join governing body FIFA's line of official World Cup products.
The 55,000-seat Fonte Nova stadium will host three Confederations Cup matches in June and six World Cup fixtures.
Sunday's incident drew an immediate backlash on social media sites such as Facebook and Twitter, which were inundated with messages criticising the fans' actions.
"What a disgrace. The supporters' lack of respect is shameful," 25-year-old publicist Jose Silva Neto tweeted.
Vitoria fan Samuel Carvalho also expressed his concern on the microblog."Bahia fans have tarnished our name at the Fonte Nova stadium," he wrote."FIFA, take notice."