A bomb has exploded outside the house of a bodyguard of Shi'ite cleric Moqtada al-Sadr in the southern Iraqi city of Najaf, killing at least six people.
The blast also injured eight people. The holy Shi'ite city of Najaf has been relatively calm compared to central Iraq, where a Sunni insurgency is raging.
Earlier, an Iraqi woman suicide bomber blew herself up outside a US military office in the northern town of Tal Afar, killing at least five others and injuring 53.
It was believed to be the first attack by a female suicide bomber since the insurgency began.
The bomb targeted Iraqi citizens filing for compensation at a Civil Military Operations Centre. Iraqis visit such centres to claim compensation if they lose relatives, or suffer damage to property, because of US military action.
The centre was opened after a joint Iraqi-US military operation which US forces said had effectively rid Tal Afar of what they called 'terrorists and foreign fighters'.
A total of 150 rebels were killed and some 700 suspects arrested during the operation in the town located between Mosul and the Syrian border.
US President George W Bush has warned of a sharp increase in violence by Iraqi insurgents in advance of voting on the country's new constitution and new government.
Speaking to reporters at the White House after a meeting with senior army commanders, Mr Bush said Iraq remained a key battlefront in the so-called 'war on terror'.
