An experimental "tweet-wall" on giant TVs in the main hall of the EU summit in Brussels was shut down to avoid causing embarrassment to Silvio Berlusconi after being hijacked by Italian Twitter users who bombarded it with messages calling their prime minister "a mafioso" and "a paedophile".

Postings on the microblogging site tagged "#EUCO" were automatically fed to a pair of large plasma screens in the main hall of the Brussels building in which the 27 leaders of Europe were meeting to discuss a response to the eurozone debt crisis.

But soon after it was launched yesterday, Italian twitter users found out about it and flooded it with anti-Berlusconi messages.

After only two hours, the "tweet-wall" was replaced by anodyne footage of the summit proceedings and the European Council logo.

"Berlusconi pays for sex, for votes, for mafia protection, for everything he can buy. What he cannot buy will be stolen," one tweet read.

"Berlusconi is a mafioso but he make laws for be not judged," said another.

At around 3pm, the Euro-blogger Joe Litobarski realised what was happening and wrote: "Uh oh. Italians have realised tweets tagged #EUCO shown on Twitter wall at #EU Council meeting – expect mayhem".

But it was the messages sent by mpietropoli, an Italian designer, that caused the council press team to take down the system when he started bombarding it with quotes from the Italian leader, including some praising Mussolini.

"Mussolini never killed anyone. Mussolini used to send people on vacation in internal exile," he posted – a quote from the PM.

"[I cannot] think that there are so many pricks around who would vote against their own best interests," mpietropoli also tweeted – another Berlusconi quote.

"We had the tweet-wall up for two hours in the main hall, but it wasn't moderated and a lot of the tweets were ... well, very, very frank," Dana Manescu, the council press team official who organised the wall, said.

"The point was not to show insulting messages about Berlusconi. If anyone from the Italian delegation saw it, it would hurt their sensibility."