Complex sentence: Al-Qaeda in Iraq claimed that the bombing was in retaliation for a recent offensive against the Iraqi insurgency, but the groups leader Abu Musab al-Zarqawi released an audio tape on the same day declaring war against Shias in Iraq.
Split into simpler sentences: Al-Qaeda in Iraq claimed that the bombing was in retaliation for a recent offensive against the Iraqi insurgency. Although, the groups leader Abu Musab al-Zarqawi released an audio tape on the same day declaring war against Shias in Iraq.