A suicide car bomber has killed at least seven Iraqis outside a US base in the Iraqi capital, Baghdad doctors and American military officials report.
Ambulances rushed to the scene after the blast
Police officers who apparently stopped the car outside Camp Cuervo were killed along with the bomber and civilians waiting at a nearby petrol station.
A top civil servant and a university professor were also killed in the city and a US soldier died near Baghdad.
Elsewhere, reports have emerged of the killing of two Iraqi journalists.
Sunday's attacks came as the issue of the treatment of prisoners by coalition forces resurfaced.
Iraq's interim President, Ghazi Yawer, rejected US proposals to demolish the notorious Abu Ghraib prison near Baghdad on grounds of cost.
"It's a prison that we spent more than $100m building," he told the US ABC television network. "We are people that need every single dollar we have... instead of demolishing and rebuilding."
The US has announced separately that it plans to close another major detention centre, Camp Cropper at Baghdad airport, after the 30 June transfer of power to the Iraqi administration.
Day of bloodshed
Two foreign hostages, a Turk and an Egyptian, were released on Sunday after 10 days in captivity, mediators said. The day was otherwise marked by violence in and around the capital.
The Baghdad suicide bomber was intercepted at about 0915 (0515 GMT) as the car speeded on the wrong side of the road towards Camp Cuervo in Rustamiya district.
The explosion happened near a busy petrol station
A US military spokesperson said about 12 Iraqis had died in the blast and 13 had been wounded but hospital sources put the death toll at seven. There were no American casualties.
Eight civilian cars were badly damaged, an Iraqi police official added.
In other violent incidents:
- A rocket attack on coalition headquarters in Baghdad caused no casualties;
Overnight fighting in the Shia slum of Sadr City left six Iraqis dead, according to Shia militants;
In Taji, a town 20 kilometres (12 miles) to the north of Baghdad,
a roadside bomb killed one US soldier and wounded two - the American military said it killed one attacker;
Reuters news agency reported that the bodies of two Iraqi journalists had been found; they were reportedly killed in the western town of Qaim on Saturday.
The government official shot dead in the city's Ghazalia district was Kamal al-Jarrah, director of cultural relations at the Iraqi education ministry.
A separate gun attack at Baghdad University took the life of geography professor Sabri al-Bayati.
The attack on Mr Jarrah, 63, was the latest in a spate of ambushes on officials:
- Interim Deputy Foreign Minister Bassam Qubba was killed on Saturday as he left for work in the al-Azimiya district;
Deputy Health Minister Ammar Safar escaped an attempt on his life in the same district a few days earlier;
The head of Iraq's border guards, General Hussein Mustapha, said he had narrowly escaped an ambush on Saturday on a Baghdad road.
The BBC's Barnaby Phillips in Baghdad says the message from the gunmen to anyone involved in the interim government is clear and chilling - that they are all targets and their lives are in danger.
US Secretary of State Colin Powell said it was hard to protect "an entire government".
"It is going to be a dangerous period and these murderers have to be defeated," he said in Washington.