The great gold dome of the mosque was already severely damaged after a February 2006 attack.
Police have imposed a curfew / military law on the Sunni city, 95km north of Baghdad, amid fears the bombing might worsen sectarian tensions. State television reports said that a similar indefinite curfew would be imposed in Baghdad.
"I was near the shrine when I heard big explosions that sent a thick cloud of dust in the sky covering the entire area, I quickly ran to the street from where I could see the shrine clearly. I saw one of the minarets was down. Seven minutes later as I was watching the shrine, another explosion occurred and the second minaret came crumbling down."
- witness to the attack
Shades of 9/11.