The Islamic State of Iraq, an al Qaeda-linked group, claimed responsibility for the attacks. In a statement, posted on radical jihadist websites, the group praised the operation calling it a "new phase."
MORE: http://www.cnn.com/2012/07/24/world/meast/iraq-unrest/index.html?hpt=imi_c2
See also...
Militants clash with security forces in Iraq
http://www.cnn.com/2012/07/26/world/meast/iraq-violence/index.html?hpt=imi_c2
