The commander of a new unit set up to fight insurgents in Iraq has been shot dead in Baghdad.
A grieving woman at the scene of the killing of Wael Rubaie
Iraqi officials say Wael Rubaie, head of operations at the Ministry for National Security, and his driver were killed on their way to work.
Also in Baghdad, US and Iraqi troops carrying out searches say they have arrested nearly 300 insurgents.
Elsewhere, car and suicide bombings killed at least 16 people and injured more than 100.
A recent surge in violence across Iraq is estimated to have killed more than 550 people in less than a month.
Maj Gen Rubaie was appointed to command a special operations room recently set up to co-ordinate the fight against insurgents across all Iraqi ministries and with the US-led multi-national force.
Late on Monday, a car bomb exploded outside a Shia mosque in Mahmoudiya, a town south of Baghdad. At least five people were killed and more than a dozen injured.
Earlier in the day, another car bomb went off outside a popular restaurant in the Shia-dominated Talibiya area of Baghdad.
The attack hit during a busy time for the Habayibna restaurant. Several cars parked on the street outside were set ablaze.
Four people were killed in the blast and about 100 injured.
Samarra saw three co-ordinated suicide attacks on Monday
In Tuz Khurmatu in northern Iraq, a car bomb exploded killing five and wounding 13 others.
The attack happened near the council offices in the town, 88 kilometres south of Kirkuk, police said.
In Samarra in central Iraq, an attack by three suicide attackers on a US military base appears to have been thwarted, but two Iraqis were killed and nine people injured, including three US soldiers.
Two suicide bombers detonated car bombs outside the base in the centre of Samarra, 95 kilometres north of Baghdad.
A third attacker approached the base carrying explosives and was shot by soldiers, the US military said.
Iraqi police said two Iraqi men were killed and six wounded, including women and children. The US military said three soldiers sustained injuries that were not life threatening.
US military officials say 285 suspected insurgents have been detained in the joint American-Iraqi operation in western Baghdad.
Iraqi officials said police commando units backed by US forces cordoned off the road leading to Baghdad's international airport and the Abu Ghraib district, areas from which numerous insurgent attacks have been launched.
"This is the largest combined operation with Iraqi security forces to date," said US military spokesman Lt Col Clifford Kent.
"The Iraqi Security Forces have the lead in this operation while we perform shaping and supporting roles."
Seven Iraqi battalions backed by US forces launched the offensive late on Sunday. No specific troop numbers were given.
News agencies report witnesses saying the operation appeared to be winding down early on Monday.
In a separate development, radical Shia cleric Moqtada Sadr has been mediating between Sunni clerics and a Shia militia in an attempt to ease tensions caused by a recent spate of sectarian killings.