In Jerusalem, a city holy to Christians as well as Jews and Muslims, the millennium has special significance.

Some religious sects are thought to be planning mass suicides

More than 100 fundamentalist Christians - mostly from the US and Canada - have already arrived in Israel hoping to witness the return of Christ on Jerusalem's Mount of Olives some time in the year 2000.

Many of the millennialists have settled in Palestinian towns near the Mount of Olives to witness the event.

BBC's Lyse Doucet in Jerusalem: Special task forces have ben set up to monitor the cults

With thousands more expected to arrive, the Israeli authorities are worried about keeping the peace in the Holy City.

One policeman in Jerusalem was quoted as saying: "If the Messiah doesn't show up as expected, we fear some of the disappointed believers may take matters into their own hands to hasten along the end of time. Given all the problems we have here already, Israel can ill afford a Waco."

One thousand years ago, simiilar disappointment at the failure of the Second Coming to materialise is thought to have been one of the triggers for the Holy Crusades, when thousands left Europe to reclaim Jerusalem from Muslim rule.

Modern day believers say the medieval knights got it wrong because they misinterpreted the scriptures - this time it is for real.

A member of the Heaven's Gate cult which carried out a mass suicide last year

Police fear that at least three US groups may be planning a repeat of recent incidents when 39 members of the Heaven's Gate group killed themselves with poison in California in the belief that the appearance of the Hale Bopp comet heralded the arrival of a UFO that was to rescue them from earth.

Another 74 disciples of the Solar Temple group killed themselves in Canada and Switzerland.

Members of the obscure religious cult, Concerned Christians, have already been arrested after threatening to commit suicide in what they see as the fulfilment of the ancient prophecy.

Police said that the group planned to provoke a bloody shoot-out by opening fire on Israeli police and members of the group believed that this catastrophic act would hasten the prophesy.

The approach of the new millennium is also having an effect on non-religious groups.

One US-based group, the UNAIRIUS Academy of Science in Southern California, believes that a giant spaceship will land somewhere in the Caribbean.