Attacks in Baghdad mainly targeting Iraqi traffic police killed at least four people on Monday and two others were shot dead in northern Iraq, security and medical officials said.

In the deadliest violence, gunmen opened fire on a traffic police patrol near Al-Sarafiyah bridge in the Waziriyah neighbourhood of northern Baghdad.

Three people were killed and one wounded, according to an official at Medical City hospital. An interior ministry official put the toll at four killed and six wounded.

In west Baghdad's Mansur district, a roadside bomb blew up near another traffic police patrol and when an emergency crew arrived at the scene, a suicide bomber detonated his explosives vest, security officials said.

One person was killed and six wounded, officials from the interior and defence ministries said.

Three separate incidents -- two roadside bombs and a mortar attack -- in east Baghdad wounded nine policemen and two police cadets, the interior ministry official and a police officer said.

Officials often give differing tolls in the confusion following attacks in Iraq. All officials spoke on condition of anonymity.

In Mosul in northern Iraq, gunmen shot dead a woman and wounded one other person, while a roadside bomb attack also wounded one, a police officer said.

And gunmen killed a real estate agent named Saad Abbas al-Obaidi near the northern city of Kirkuk, police said.

Violence in Iraq is down markedly from its peak in 2006 and 2007 but attacks remain common. A total of 185 people were killed in violence in September, according to official figures.