The annual hajj pilgrimage that draws millions of Muslim faithful to Mecca has gone hi-tech this year, with the Saudi authorities calling in latest electronic aides to help control the vast crowds. Coping with the world's largest annual human assembly poses a security headache for Saudi Arabia -- guardian of the two holiest Muslim shrines in the cities of Mecca and Medina, the birthplaces of Islam. The ministry of religious affairs sends 3.25 million text messages each day to the mobile phones of pilgrims to inform them of correct procedures for the hajj rites so as to "prevent that which is harmful," according to ministry official Sheikh Talal al-Uqail, cited by the official SPA news agency. The messages managed by more than 3,000 clerics, translators and administrators aim to correct "errors" made by some pilgrims, the report said. At the same time, Saudi authorities follow and manage the movement of the swarms of pilgrims by means of electronic monitors which track each and every pilgrim during the five-day hajj, according to Saudi Minister of Hajj Fuad al-Farsi. The religious police meanwhile post videos and documents for the guidance of pilgrims on video-sharing website YouTube, accessible at http://www.youtube.com/user/movieshajj. And for the first time this year, the hajj is being streamed live on YouTube in cooperation with the Saudi government. The stream can be seen at youtube.com/hajjlive. More than two million Muslims flocked Saturday to Mount Arafat and its surrounding plain, marking the peak day of the hajj. There were no immediate reports of major incidents as security officials focused on crowd control. "Things are going well and according to plan," interior ministry spokesman General Mansur al-Turki told AFP. The hajj is one of the five pillars of Islam and must be performed at least once in a lifetime by all those who are able to make the journey.