An "unbalanced woman" jumped the barriers in St Peter's Basilica and knocked down Pope Benedict XVI as he walked down the main aisle to begin Christmas Eve Mass, a Vatican spokesman said on Thursday.
But according to the New York Times, the pope quickly got back on his feet and celebrated Mass before thousands of the faithful, urging them in his homily to become "truly vigilant people".
Television images showed a woman in red leap toward Benedict, 82, as he began to walk up the central aisle, as the police and bodyguards scrambled to his aid.
The woman also knocked down Cardinal Roger Etchegaray, said the spokesman, the Rev. Federico Lombardi.
The Vatican police took the woman in for questioning, and Cardinal Etchegaray was taken to an emergency room for a check up, the news agency ANSA reported.
The woman did not appear to have "malicious intentions", ANSA said.
It was not immediately clear whether she was the same woman stopped by the police last year after trying to lunge at the pope as he left the Basilica.
Image: Pope Benedict XVI is assisted as he leads the Christmas mass in Saint Peter's Basilica at the Vatican after he was knocked over by an 'unbalanced woman' | Photograph: Max Rossi/Reuters