Baghdad's heavily fortified "Green Zone" came under heavy rocket or mortar attack today, and police said at least two people had been killed outside the government and diplomatic compound.
In a separate incident, gunmen in three cars opened fire on pedestrians in a religiously mixed southern Baghdad district, killing at least seven and wounding 16, police said.
The US-protected Green Zone in central Baghdad area was often hit at the height of sectarian violence a year ago, but attacks have become rarer with improved security across Iraq.
In northern Mosul, a suicide truck bomber killed 10 Iraqi soldiers and wounded 30, including civilians, in an attack on an Iraqi army base, the Interior Ministry said. US commanders describe Mosul as al Qaeda's last urban stronghold in Iraq.
The US military said it killed 12 insurgents in a raid on a house east of Baquba after local media reported an operation in the town of Balad Ruz, 70 km (45 miles) northeast of Baghdad.
"Six of the terrorists killed had shaved their bodies, which is consistent with final preparation for suicide operations," spokesman Major Winfield Danielson said.
Mosul and Baquba are the capitals of two of four northern provinces where offensives were launched this year against Sunni Islamist al Qaeda fighters who regrouped there after being driven out of strongholds around Baghdad and western Anbar.
While there was no immediate indication of who was responsible for today's Green Zone attacks, the US military has blamed past missile strikes on rogue elements of anti-US Shia cleric Moqtada al-Sadr's Mehdi Army militia. Sadr last month renewed a seven-month-old ceasefire for his militia, which the US military has credited for contributing to sharp falls in violence across Iraq.
However, there are fears the ceasefire may be unravelling after Mehdi Army fighters clashed with Iraqi and US forces in the southern city of Kut and southern Baghdad last week.
The Iraq war last week moved into its sixth year, US President George W. Bush marking the anniversary of the US-led invasion to topple Saddam Hussein with an upbeat speech in which he said the United States was on track to victory.
Tens of thousands of Iraqis have died in the insurgency and sectarian violence between majority Shia and minority Sunni Muslims since the invasion, although attacks across Iraq have fallen 60 per cent since last June, US commanders in Iraq say.
With the number of US troops killed in Iraq nearing 4,000, the war remains a major issue in the US presidential campaign.