Vatican City, Dec 25 (DPA) Pope Benedict XVI late Thursday fell briefly in a scuffle when a woman trying to get to the pontiff jumped a cordon barrier as Christmas midnight Mass began in St Peter's Basilica.

Shortly after the incident, the 82-year-old pontiff, who appeared unharmed, again took hold of the golden cross he was carrying before being knocked down, and continued to lead the procession for the beginning of the Mass.

Benedict, clad in gold-embroidered robes and wearing his bishop's mitre, then presided over the rest of the ceremony and delivered his homily.

French Cardinal Roger Etchegaray, who also fell in the scuffle, received some unspecified medical attention, news reports said.

The woman who was wearing red - initial reports had mentioned a man - was detained by Vatican guards. She is believed to suffer from psychological problems, ANSA news agency reported.

The Vatican's traditional midnight Mass this year began two hours earlier than usual in order to allow the pontiff some rest.

Earlier this month the Vatican denied Italian media speculation that the decision to begin the mass at 10 p.m. (2100 GMT) was due to unspecified "health problems" afflicting the German-born pontiff.

At the time, papal spokesman Father Federico Lombardi explained that the move - first announced by the Vatican in October - aimed to "tire the Pope a bit less," giving him a few extra hours sleep before his Christmas Day duties.

On Thursday night, thousands of people flocked to St Peter's Basilica for the ceremony. Many more followed the proceedings on giant video screens in St Peter's Square on a mild but damp winter's night.