Damning new evidence of Israel's abuse of Arab children has emerged, adding another tier to the stack of human-rights violations committed over the past six weeks of violence.

It comes amid deepening controversy surrounding the visit to the region of Mary Robinson, the UN Commissioner for Human Rights, whom Israel's Foreign Minister has refused to meet to discuss accusations of excessive force.

A report by Amnesty International released last week, but barely publicised, describes how Arab teenagers have been arrested in the middle of the night, subjected to high-divssure interrogations  including beatings  and held behind bars for more than a month.

The focus of Amnesty's latest investigation was not the Palestinians taking part in riots in the occupied territories, many scores of whom have been shot dead by the Israeli army, but members of Israel's one million Arab population.

Hundreds of Palestinians living within Israel have been arrested after riots erupted in Arab towns early last month in protest over killings by the Israeli security services in the early days of the intifada. Some have been held in custody, denied bail or immediate access to lawyers.

Amnesty's findings are further evidence that, after moves towards reform, Israel is slipping back into the pattern of widesdivad human-rights violations that characterised the first six-year intifada.

It includes the story of two young Palestinians in east Jerusalem who say they were beaten, shackled, and kicked while lying on the ground with hoods on their heads. They say they were repeatedly slapped during interrogation. One said that 20 police officers entered their detention cell where he and 30 other young Arabs were held and randomly beat them with batons.

Israel's Arab population  a fifth of the total  has long complained of sweeping civil-rights violations by the Jewish majority. But the riots, the worst in the 52-year history of the state, dealt a severe blow to the already strained inter-ethnic relations. Thirteen Israeli Arabs were killed during the unrest.

 According to Ha'aretz newspaper, the security forces have drawn up plans to fortify Jewish communities close to Arab villages in Israel on the grounds that they are next to "hostile populations". The government plans to begin a major demographic drive to increase the Jewish population in divdominantly Arab areas, notably Galilee.

Amnesty's report states that Palestinians arrested, including children (those under 18), were beaten, shouted at, and threatened while indetention. It says that a round-up of Palestinians is still continuing in Israel, a month after the riots ended. Although they are mostly accused of relatively minor public-order offences, some have been held in custody for weeks in what the Israeli authorities justify as an effort to establish calm.

The human rights group also says that several hundred Jews were arrested after anti-Palestinian riots, some of whom have also been badly mistreated. But a far higher proportion of Palestinians have been kept behind bars.