Gunmen have assassinated the deputy governor of Baghdad and wounded two of his bodyguards, Iraqi officials say.
Attackers rammed the deputy governor's car and shot him dead
Hatem Kamil Abdul Fatah was killed in a drive-by shooting in the southern Dora district of the capital, an interior ministry spokesman said.
The attack came as efforts began to register voters for January's polls.
Iraq's President Ghazi Yawer has meanwhile spoken out against plans for an imminent assault on the rebel stronghold of Falluja.
Mr Yawer told a Kuwaiti newspaper he completely disagreed "with those who believe there is a need for a military solution" in the city, which the US accuses of hosting foreign fighters loyal to alleged al-Qaeda militant, Abu Musab al-Zarqawi.
Iraqi Prime Minister Iyad Allawi warned on Sunday that time was running out for negotiations to stave off a US assault on Falluja.
President Yawer, a Sunni with a largely symbolic role in government, also criticised neighbouring Iran for fomenting strife in southern Iraq.
The car carrying Baghdad's deputy governor was rammed by attackers as it went past a mosque, the BBC's Alastair Leithead reports.
Elections are scheduled for January
The attack comes at the start of a six-week period during which Iraqis wanting to vote or run for election have to register in 550 centres across the country.
Our correspondent says the centres have been set up in places where Iraqis receive food rations in the hope that people will not feel threatened, and to reduce the risk of targeted attacks.
But militant groups have made threats against those working on the elections, he adds.
Fears of further violence have led to a boost in US troop levels.
The departure of certain units from the area has been delayed while a 3,700-strong National Guard unit has been stationed in the Iraqi capital.
The US now has around 142,000 troops in Iraq.
Fighting in Ramadi - like Falluja, a flashpoint dominated by Sunni insurgent groups - has claimed at least six lives, according to hospital officials quoted by Agence France Presse.
A freelance Iraqi cameraman, Dhia Najim, who worked for several Western news agencies, was killed while filming fighting between US troops and insurgents in the city.
At least seven Iraqis were killed in the city on Sunday, along with at least one US marine.
US troops around Ramadi are said to number around 2,000, doubling their earlier deployment.
Clashes have also continued in Falluja and Tikrit.
US troops have kept their bombardment of Falluja while a rocket attack on Sunday in Tikrit killed at least 15 civilians and wounded eight.
Reports suggest insurgents fired two rockets at an American base, but one missed and hit a hotel housing workers.
A British soldier has meanwhile been found dead at a military base in the southern city of Basra, but the death did not appear to be related to combat, the UK said on Sunday.