VATICAN CITY - Pope Francis urged the world in his Christmas message on Friday to unite to end atrocities by Islamist militants that he said were causing immense suffering in many countries.

Security was tight at the Vatican as Francis, marking the third Christmas since his election in 2013, read his traditional Christmas Day "Urbi et Orbi" (to the city and the world) address from the central balcony of St. Peter's Basilica.

Tens of thousands of people had to have their bags checked as they entered the Vatican area and then go through airport-style screening if they wanted to enter St. Peter's Square.

Counter-terrorist police with machine guns discreetly patrolled the area in unmarked vans with dark windows.

After calling for an end to the civil wars in Syria and Libya, the pope said:

"May the attention of the international community be unanimously directed to ending the atrocities which in those countries, as well as in Iraq, Libya, Yemen and sub-Saharan Africa, even now reap numerous victims, cause immense suffering and do not even spare the historical and cultural patrimony of entire peoples."

He was clearly referring to Islamic State militants who have carried out numerous attacks in those countries and destroyed many cultural heritage sites. In October, Islamic State militants blew up the Arch of Triumph, a jewel in the exquisite collection of ruins in the Syrian oasis city of Palmyra.(Reuters)