Baghdad's deputy police chief has been killed outside his home in the south of the Iraqi capital.
Yet another day in the run-up to elections is marked by violence
Brigadier Amer Ali Nayef was shot dead along with his son, Khalid Amer - also a policeman - as they left the family home for work in the south of the city.
Violence has been escalating in Iraq ahead of elections due on 30 January.
This is the second killing of a senior official in less than a week. Last Tuesday, Baghdad governor Ali al-Haidri was shot dead in a roadside ambush.
Hours after the incident, Iraq's interim Prime Minister Ayad Allawi announced the arrest of 147 suspected insurgents throughout the country on Monday.
They included Raad al-Doury, leader of Jaish Mohammed, (Muhammad's Army), who was arrested just days after he took over from the previous chief, himself detained two months earlier.
"Every day the terrorists name a new leader, we capture him and they will stand trial," Mr Allawi told a news conference.
Brig Nayef and his son had just left their home in the Dora area of the city in a car when they were intercepted by gunmen in two cars.
The attackers sprayed machine-gun fire at the police chief's vehicle, killing both men instantly, before fleeing the scene.
INSURGENT VIOLENCE MOUNTS
10 Jan: Baghdad deputy police chief and son shot dead
7 Jan: Seven US soldiers killed in bomb attack in Baghdad
6 Jan: Bodies of 18 Iraqis contracted to work at US base found outside Mosul
5 Jan: At least 25 Iraqis killed in three separate attacks in central Iraq
4 Jan: The governor of Baghdad, 14 Iraqis and five US soldiers killed in separate attacks
3 Jan: More than 20 people killed in a day of violence across Iraq
2 Jan: At least 23 Iraqi soldiers killed by a car bomb in Balad
The attack came minutes after a suicide bomber blew up his car at the gate of a police station in the capital, killing at least three policemen.
Several others were wounded in the blast in the southern Zafaraniya area of the city.
The US military also reported two deaths of servicemen on Sunday. A soldier assigned to Task Force Baghdad was killed by a roadside bomb, it said, without detailing the location.
In a separate incident, a marine was killed in action in restive Anbar province, the military said.
And in Seoul, the South Korean foreign ministry said it is checking reports that one or two of its nationals may have been kidnapped in Iraq.
A militant website threatened to kill two hostages if South Korea's 3,600 troops in Iraq are not withdrawn but at present no missing South Koreans are reported.
The death of the deputy police chief is another major blow to the Iraqi security forces at a time when they are preparing to play a major role protecting the elections, says the BBC's Jim Muir in Baghdad.
The militants have vowed to disrupt the polls, however US forces have brought in extra troops, and a special security plan is being implemented to try to reduce the risks.
Also on Monday, the Iraqi interim government has officially asked Syria to hand over a number of people it says are using Syrian territory to plan and finance the insurgency in Iraq.
They include Saddam Hussein's half-brother, Sabaawi, and the former Iraqi intelligence chief, Taher Habboush.
The comments by the Iraqi interim Deputy Prime Minister Barham Saleh in a BBC interview, come after the defence minister, Hazem Shaalan, on Saturday showed journalists a video which he said provided new evidence that Syria and Iran were backing the insurgency.
A Syrian official has denounced Iraq's repeated accusations as irresponsible and on Sunday an editorial in the Syrian state newspaper, Ath-Thawra, said the video had been fabricated.