Hundreds of thousands mourners observing chelum of Hazarat Imam Hussein (PBUH) in Karbala. Men, women, children and elderly wearing black clothes, marched and chanted religious slogans renewing homage to Prophet Mohammed's grandson Hussain (PBUH), who was killed along with his household and companions in the land of Karbala some 1400 years ago. Iraqi security forces, including snipers and undercover agents, have deployed in force in Karbala to protect millions of pilgrims gathered for a ceremony. Karbala provincial governor Akeel al-Khazali estimated that more than 10 million people have already arrived in the city for the ceremony, including 150,000 Shiites from abroad.