Iraq's new prime minister has failed to put together a complete cabinet in time for ministers' swearing-in.
Jaafari's government was sworn in despite gaps in the list
Seven posts in Prime Minister Ibrahim Jaafari's government - including the defence and oil ministries - remain empty amid partisan haggling.
The power broker for minority Sunnis, outgoing President Ghazi al-Yawer, stayed away from Tuesday's ceremony.
Mr Jaafari must bring credible Sunnis into his government to undercut the insurgency, the BBC's Jim Muir says.
Without them, the new government's chances of reaching out to disaffected Sunnis - long-time rulers of Iraq who now find themselves out of power - would be greatly reduced, our correspondent in Baghdad says.
Not until the swearing-in ceremony was it clear that critical positions remained to be filled.
The defence ministry has proved a particular sticking point, with an unnamed source telling AFP news agency that Sunni parties had rejected the three candidates offered to them.
The failure to fill the seven posts is a considerable embarrassment for the prime minister, our correspondent says.
Violence has surged since the partial cabinet was agreed last week.
US-led forces were in action in several places around Iraq:
- At least 15 people are killed in a battle between coalition forces and insurgents in Ramadi, including 12 militants, an Iraqi soldier and two Iraqi civilians, the US military says
- The US military says its troops killed 12 insurgents at Qaim, near the Syrian border
- A US marine pilot is killed and another is missing after a suspected mid-air collision between two US F/A-18 Hornet jets.
Mr Jaafari highlighted the difficulties Iraq faces as he was sworn in, citing "corruption, lack of services, unemployment and mass graves", the Associated Press news agency said.
But he struck a positive note even as he outlined the challenges.
"I would like to tell the widows and orphans ... your sacrifices have not gone in vain."
After the ceremony, he told reporters that the most important thing was to find consensus, however long that took.
"We are not in a hurry," he said. "We want the choice to be accepted by all the Iraqi people."
Mr Jaafari is a Shia, the majority group in Iraq which was long denied power.
Last Thursday, Mr Jaafari announced a partial list, which was endorsed by the parliament by a large majority.
His government has 15 Shias, seven Kurds, four Sunnis and a Christian. One deputy prime minister is a Shia and another is a Kurd.
The seven posts left vacant are: oil minister, defence minister, electricity minister, industry minister, human rights minister and two deputy prime ministers.
Mr Jaafari himself is acting defence minister, while Deputy Prime Minister Ahmed Chalabi is acting oil minister.