Shia v Sunni

Shi'ite muslims marching across the al-Aima bridge where hundreds of Shia's had lost their lives just days before, once again came under attack from Sunnis.

It happened as the Shi'ites approached an Iraqi army checkpoint. Soldiers at the checkpoint fired warning shots into the air, Sunnis used this as an excuse claiming that they thought they were under attack.
The two sides exchanged fire and as a result a 12yr old girl was killed in the crossfire.

In separate attacks at least two Sunnis were killed and four injured when Shi'ites opened fire on the Mizael Basha and al-Rashidiya mosques in Basra.

I thought they would at least wait until the three days of mourning were over before they started the butchering.