VATICAN CITY (Reuters) -- A woman the Vatican described as unstable jumped over a barricade, lunged at Pope Benedict and dragged him to the floor at the start of his Christmas Eve mass in St Peter's Basilica.
The 82-year-old pope was apparently not harmed and went on to finish the two-hour service, but an elderly French cardinal in the papal procession fell to the floor and was taken to hospital with a broken leg.
Television pictures showed the woman, dressed in a red top, jumping over the barricade and hurling herself at the pope, provoking screams from members of the congregation.
The woman grabbed the pontiff's vestments as she was tackled by a security guard and both she and the pope then fell to the marble floor.
Vatican spokesman Father Federico Lombardi said the woman, whom he described as "unstable," was the same person who tried to jump a barricade to get close to the pope at last year's Christmas Mass.
The pope, dressed in gold and white vestments, was helped up by security men and after a few seconds continued the procession up the centre aisle to celebrate the Mass. He seemed calm and unfazed during the rest of the ceremony.
But French Cardinal Roger Etchegaray, 87, who has been in frail health recently, fell to the floor and was taken away in a wheelchair. He suffered a broken femur, Lombardi said.
The woman was detained for questioning by Vatican security police and was not immediately identified.
There have been relatively few security breaches in Benedict's pontificate, which began in 2005. In 2007 a German man jumped over a barricade in St Peter's Square as the pope's jeep was passing during a general audience and tried to board the vehicle.
The most serious attack on a pope in the Vatican came in 1981 when Turkish gunman Mehmet Ali Agca, shot and nearly killed Pope John Paul II in St Peter's Square.
The incident, which left Vatican security guards visibly shaken and bishops stunned, happened at the start of a Mass at which Benedict led the world's some 1.1 billion Roman Catholics into Christmas.
It again raised the question of how vulnerable the pope can be if he wants to maintain contact with the public.
"It's surprising that it happened inside St Peter's, because the security there has changed a great deal in recent years and is much more tight than it used to be," the Archbishop of Westminster Vincent Nichols, leader of Catholics in England and Wales, told the BBC.
"But there it is, I'm sure those arrangements will be reviewed and greater care will be taken," he said.
While visitors to St Peter's Basilica must pass through metal detectors and spot checks, security once they get inside is relatively light. Vatican security is shared by a police force and Swiss Guards.
In his homily to more than 10,000 people inside Christendom's largest church, the pope urged the faithful to rediscover the simplicity of the nativity message.
He recounted the traditional Christmas story of Christ's birth in a manger in Bethlehem and urged Catholics to put aside the complexities and burdens of daily life and rediscover the path to God.