rafafBombers struck a police patrol in central Baghdad on Monday, as Iraq's embattled government celebrated the arrest of an alleged terror kingpin accused of triggering a sectarian war.
Meanwhile a war of words continued between the Iraqi government and Kurdish leaders, who have refused to fly the national flag in their autonomous region.
Meanwhile, interior ministry spokesman Brigadier General Abdelkarim Khalaf said three officers were critically wounded in the attack in Al-Wabhiq Square in the largely Shiite and Christian district of Karrada.
Violence also continued just north of the capital in Diyala province, which is in the grip of a vicious turf-war between rival Sunni and Shiite factions. At least one civilian was shot dead and five more wounded, police said.
The violence, which was low-key by Iraq's bloody standards, followed the arrest of a man described by Iraqi officials as the number two figure in the Sunni militant movement Al-Qaeda in Iraq.
"This is a very important development," deputy prime minister Barham Saleh said.
"Deliberate intelligence work both by Iraqi forces as well as multinational forces has dealt a very severe blow to the Al-Qaeda organisation in Iraq.
"And it is also significant because this man is believed to have been responsible for the attack on the shrines in Samarra, which led to the sectarian violence that we have seen," he said.
In February, extremists demolished the golden dome of a revered Shiite shrine, triggering a series of sectarian reprisals which have pushed Iraq to the brink of all-out civil war.
Alongside that conflict, Sunni insurgents have continued to target the US-led coalition forces protecting Prime Minister Nuri al-Maliki's government.
Two US marines died Sunday after "enemy action" in the western province of Al-Anbar, a bastion of the Sunni insurgency, the military said.
The latest deaths brought the US military's losses in Iraq since the March 2003 invasion to 2,647, according sources.
At the same time, tempers frayed on Iraq's other main faultline -- the divide between Arab leaders in Baghdad and the Kurdish minority in the north.
Last week, the president of the autonomous Kurdish region, Massud Barzani, set off a war of words when he banned the use of the Iraqi banner, branding it a symbol of ousted leader Saddam Hussein's hated regime.
Maliki responded with an order that the national flag should fly until Iraq's parliament, which is to reconvene on Tuesday after a recess, decides on a new symbol on which the whole country can agree.
Barzani's response was uncompromising, and raised the spectre of resurgent separatist feelings among the Kurds.
"This flag of chauvinism will not be hoisted on Kurdish land in Iraq. The procedure all over the world is that when a dictatorial regime is abolished, all that is related to it should also be abolished," he said.
"This has happened across the world, and we do not know who decided that the present flag be the flag of Iraq. Was it decided by the parliament or by the cabinet?" he asked, according to a statement from his office.
Attempting to play honest broker, Iraq's Kurdish president, Jalal Talabani, weighed into the debate, supporting Barzani's opposition to the old banner but calling for patience while a new one is adopted.
"The Iraqi flag to be adopted by the Iraqi parliament in accordance with the constitution will be a holy and glorified one, recognized by all," he said.