 The explosion occurred just two days after a four-day curfew banning vehicle movement in the city was lifted after the al-Askari Mosque bombing (2007), and just hours after 10,000 US troops began the Arrowhead Ripper offensive to the north of Baghdad.Because the site was a Shia mosque, the bombing is presumed to have been the work of Sunnis.The Sinak area where the explosion took place was also the targeted by a suicide car bomber on 28 May 2007, which resulted in 21 deaths.