Fears are growing among police and security agencies that the London Olympics will be targeted by an alliance of European and British anarchist groups.

Officials believe that anti-austerity protest groups will focus on disrupting the games, which will provide a major platform for any protest message.

Italian protest group, the Informal Anarchist Federation (FAI) has made a clear threat to the games.

On anarchist website 325.nostate, the FAI writes: "In the United Kingdom of clockwork control and domestication, we're some of the "unpatriotic ones" who find the 2012 Olympics, with the ensuing spectacle of wealth, frankly offensive.

"We have no inhibition to use guerrilla activity to hurt the national image and paralyse the economy, howeve we can. Because, simply, we don't want rich tourists, we want civil war."

The Anonymous hacking group has also signalled plans to disrupt the games, suggesting a large scale peaceful protest to show that "we will not be dictated to" and that "these streets are our streets".

Royal United Services research analyst Valentina Soria told the Guardian that the situation could "turn nasty" as certain anarchist groups will look to provoke a violent response from the police.

She said: "We have seen the anarchists in Italy supporting the Greek anarchists more recently and they may join anarchists already in the UK for some king of disruption of the Olympics."

The scale of the Olympic security effort has been well publicised, with a military presence of around 13,500 personnel protecting the capital, including the use of fighter jets and surface to air missiles.

Police and security personnel are braced for protests from groups both large and small as the eyes of the world turn on London for the games.

Occupy London protester Kerry-Anne Mendoza told the Evening Standard there is a plan for, "the greatest act of civil disobedience of our time' during the event.

Mendoza claims several protest groups will unite under the banner Reclaim London and use the Olympics as an opportunity for the "unheard majority".

Meanwhile parental rights group Fathers 4 Justice and other splinter groups have also promised disruption attempts.

The police have been granted additional powers to combat protests during the games, with clauses in the London Olympic Games and Games act 2006 seemingly giving officers the ability to seize placards and political posters and even enter private homes to seize protest materials.