An Italian Cabinet minister called today for rapists to be chemically castrated, amid a growing row over vigilante attacks on immigrants that have followed a series of rapes blamed on foreigners.

Roberto Maroni, the Interior Minister, urged Italians not to take the law into their own hands after masked youths armed with wooden clubs smashed up a kebab bar near the scene of a rape at Caffarella Park on the Appian Way in Rome at the weekend.

Five Romanians were beaten savagely in the raid, and two are in a serious condition.

The attack followed an incident on St Valentine's Day in which a 14-year-old girl was raped and her 16-year-old boyfriend beaten up in the park, which is used by courting couples.

Also at the weekend a 21-year-old Bolivian girl was raped in Milan by a man described as North African, while in Bologna a Tunisian who had just been released from prison after being held on drugs offences was re-arrested for allegedly raping a 15-year-old local girl.

Roberto Calderoli of the Northern League, who is Minister for Simplification of Laws in the centre-right government of Silvio Berlusconi, said that chemical castration was "the only answer" when teenage girls were being attacked. "Talk of rehabilitation is not enough," he told La Stampa. "Society must defend itself".

Mr Maroni said that the Government would push through an emergency decree this week speeding up legislation aimed at creating "groups of unnamed citizens" to "assist the police by bringing to their attention events which might be damaging to urban security". The decree will also ban magistrates from releasing into house arrest those accused of crimes involving sexual violence.

Mr Maroni said that creating groups of "concerned citizens" was not the same as condoning vigilante patrols, known as ronde. However Pierferdinando Casini, of the Christian Democratic UDC, said that the Government was "flailing around" after coming to power on a promise to resolve the crime and immigration problem nearly a year ago. "What we need are more police," he said.

Marco Minniti, the shadow interior minister, said that there was "a very fine line" between vigilantes and neighbourhood watch groups. Enzo Letizia, head of the police trades union, said that because of public spending cuts by the Berlusconi government the police were so badly underfunded that there was no money to maintain the country's 25,000 police patrol cars, 500 of which were currently out of commission.

Gianni Alemanno, the rightwing mayor of Rome, who visited the Cafferella Park area at the weekend to meet angry residents, said that police patrols should be stepped up in isolated areas where the suburbs merged into the countryside. Rapists must know they face "a definitive sentence", the mayor said, and all illegal gypsy camps in Rome would be dismantled. There was no justification, however, for "intolerance and do-it-yourself justice".

The number of Romanians arrested for rape annually has risen from 170 five years ago to nearly 500, followed by Moroccans (300), Albanians (150) and Tunisians (120), according to official crime figures. The proportion of immigrants accused of crimes of sexual violence has risen from 9 per cent of the total ten years to 40 per cent today. A taskforce of 25 Romanian police officers arrived in Rome today to help the Italian authorities investigate the recent spate of rapes.

Earlier this month a homeless Indian labourer was savagely attacked and set on fire by local youths as he slept on a bench in the coastal town of Nettuno, 70km south of Rome. Last month four Romanian immigrants were arrested at Guidonia, near Rome, for allegedly gang-raping an Italian woman. The day after the attack, Albanians and Romanians were beaten up by a mob and Romanian-owned shops were fire-bombed.

A Bill currently going through Parliament includes a provision calling for a census of homeless people to be entered into a database held by the Interior Ministry. Doctors would be allowed to report illegal immigrants to the authorities, something which has been banned on privacy grounds since 1998.

Last month Mr Berlusconi vowed to increase tenfold the number of soldiers helping police to patrol city streets, taking the total to 30,000. But in a characteristic gaffe he said that to guarantee public safety, "we would have to have as many soldiers as beautiful women, and I don't think that would be possible".

The recent attacks echo the rape and murder of a woman in Rome in October 2007 for which a Romanian man has been convicted. That attack helped to make crime and immigration one of the main campaign issues in last year's elections.

Thousands of illegal immigrants continue to arrive at the tiny Italian island of Lampedusa, off the North African coast, where there have been riots at the overcrowded detention centre.

Last November, four youths beat up and set alight a homeless Italian man sleeping on a park bench in Padova. Also last year, a 63-year-old Ghanaian immigrant sitting on a park bench in Milan was severely beaten by youths with baseball bats.

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