Commotion: Pope Benedict XVI is helped to his seat moments after a woman jumped barriers and knocked the pontiff down The Pope has been knocked to the ground tonight during Midnight Mass at St Peter's Basilica by the same woman who jumped the barriers last year, according to reports.
Pope Benedict XVI was walking down the aisle to begin the traditional Christmas Eve service when the woman made her move.
The pontiff's security guards rushed forward to help him back to his feet.
The Rev Ciro Benedettini said the Pope quickly got up off the marble floor, aided by the Master of Ceremonies, and was unhurt.
Slow motion television footage showed a plastic chair flying into the air as bodyguards rushed to the scene.
video of this year's Mass and 2008's attack on Pope...
- Video: Pope knocked down at Christmas, click here...
- Video: Person charges at Pope, click here...
Pope Benedict, 82, calmly resumed his walk to the basilica's main altar and began the Mass to applause from worshippers.
Rev Benedettini said the woman who pushed the Pope appeared to be mentally unstable and had been arrested by Vatican police.
He said she also knocked down Cardinal Roger Etchegaray, 87, who was taken to hospital after suffering a broken leg as a result of the attack.
Vatican spokesman Father Federico Lombardi said the woman was the same person who tried to jump a barricade to get close to the Pope at last year's Christmas Mass - but was quickly blocked on the ground by security (scroll down to see video of last year's attempted attack).
Woman in red top (right) can be seen launching herself over the barrier towards the PopeThis year, Midnight Mass was brought forward to 10pm to ensure the Pope had enough energy to deliver his Christmas message the following day.
Pope Benedict XVI needed ‘time to rest’ before his duties on Christmas Day, Vatican officials said.
It is the first time the traditional ceremony has begun at a time other than midnight and will ensure the Pope is refreshed in time for his Urbi et Orbi blessing from St Peter’s at noon.
Vatican officials have been quick to deny the Pope was ‘anything other than in good health’ but added: ‘The change is just a precaution you would take for any 82-year-old man.
Close call: Vatican security guards (in black) run past choristers towards the Pope after he was pushed over as crowds look on 
Security scare: The Pope, who was said to be unhurt after the incident, takes Christmas Night Mass at St Peter's Basilica ‘He is very busy and the early start will mean an earlier finish.’
In the past, midnight Mass has not ended until well after 2am.
Papal spokesman Father Federico Lombardi said: 'There is no cause for concern. The Pope is in good health.
Blessing: Pope Benedict XVI celebrates the holy mass at the Vatican to mark the nativity of Jesus Christ'This was arranged a few months ago and relayed to broadcasters so they were aware for their planning.'
Cardinal Roger Etchegaray was also knocked down by the woman. He has been taken to hospital suffering a broken leg (file picture)Some local churches are also bringing forward their midnight masses to make it easier for young families and elderly worshippers to attend and return home safely afterwards.
Transport problems and the fear of encountering rowdy drunks after the pubs close are also being cited as reasons to hold services earlier.
Pope Benedict XVI, born Joseph Ratzinger in Bavaria, is the 256th Pope and was elected in 2005.
The ninth German Pope, he was forced to join the Hitler Youth as a teenager but did not participate in its activities - and has described his youth as being 'marred by a sinister regime'.
He was later conscripted into a home defence anti-aircraft unit.
At the end of the war he was taken prisoner by American troops but held only briefly.
Pope Benedict hit the headlines recently over his decision to move his controversial wartime predecessor Pius XII closer to sainthood.
Some fear that this might lead to a cancellation of his planned visit next month to Rome's synagogue.
Past security breaches
Attack: In 2007, a man leapt over a barricade in an attempt to launch himself at Pope Benedict XVI. The incident in St Peter's Square was thwarted by bodyguards and the Pope was unharmedIn June, 2007, a German man tried to jump into Pope Benedict XVI's popemobile during his weekly audience held in St Peter's Square.
As security officers wrestled the 27-year-old man to the ground, the Pope, himself German, was unharmed and didn't seem to notice the incident.
In May, 1982, Benedict's predecessor, John Paul II, was shot by Mehmet Ali Agca, a member of right-wing extremist Turkish organisation the Grey Wolves, also in St Peter's Square.
John Paul was wounded in the abdomen but made a full recovery and later forgave his would-be assassin.
source: dailymail