A series of bomb blasts in Iraq have killed more than 40 people and wounded at least 200.
Two truck bombs exploded in a Shia village near the northern city of Mosul, killing at least 28 people and injuring more than 130.
Meanwhile, Baghdad was hit by a string of bomb attacks that killed at least 18 people and wounded more than 90.
Iraqi Prime Minister Nouri Maliki has warned of an upsurge of violence ahead of next January's elections.
Insurgents "will try in any way they can to give the impression that the political process is not stable", he said in a televised news conference.
But he said the government was doing all it could to "deny them a safe environment for [the] planning and implementation of further attacks".
The BBC's Natalia Antelava in Baghdad says the Iraqi government is keen to show its troops are fully in control and capable of doing their job without the help of US forces.
But many Iraqis say this wave of violence is what they feared would happen when US troops pulled back from Iraqi cities a month ago.
Few believe the country's army - perceived by many to be corrupt - is capable of protecting them, our correspondent says.
No-one has yet claimed responsibility for Monday's attacks, but one minister said they bore the hallmark of al-Qaeda and other Sunni insurgents in Iraq.
Al-Qaeda stronghold
Truck bombs exploded nearly simultaneously in the village of Khaznah, 20km (13 miles) east of Mosul, at about 0400 (0100 GMT) on Monday.
ANALYSIS
Natalia Antelava, BBC News, Baghdad This string of attacks seems to be well co-ordinated, well organised and it certainly sends a very powerful message to the government of Iraq.
The big question now is can the government handle the security situation? They say they absolutely can.
There are forces in Iraq though that don't want this violence to stop.
And for more and more Iraqis the confidence they have in their government to protect them is decreasing.
Many see the Iraqi security services as corrupt and many fear the violence will escalate.
The blasts were so powerful they completely destroyed at least 30 houses and left a 7ft (2m) crater in the village, which is home to the tiny Shia Shabak ethnic group.
Witnesses spoke of scenes of chaos as people searched through piles of bricks, twisted metal and rubble for buried family members.
"I was sleeping on the roof and I woke up as if there was an earthquake. After that I saw a plume of smoke and dust spreading everywhere," resident Mohammed Kadhem, 37, told the AFP news agency.
"A minute later another bomb went off, knocking me off the roof on to the ground. I was struck unconscious by shrapnel and stones.
Ethnically-mixed Mosul - Iraq's second city - is considered one of the last strongholds of al-Qaeda in Iraq, and still sees frequent attacks despite a decline in violence elsewhere in the country.
Deadly blasts
However, despite security gains in Baghdad, at least three bombs went off in separate parts of the capital on Monday.
Two of the blasts appeared to be targeting labourers who were gathering in the early morning looking for work.
One of the bombs was hidden in a pile of rubbish when it went off in the western district of Hay al-Amel, killing at least seven people and wounding 46.
KEY ATTACKS AFTER US PULLBACK
7 August: A car bomb outside a mosque in Mosul kills 30 people. Six people die in attacks in Baghdad 31 July: At least 27 people die in a string of attacks outside five mosques in Baghdad 9 July: 50 killed in bomb attacks at Talafar (near Mosul), Baghdad, and elsewhere 30 June: Car bomb in Kirkuk kills at least 27 people 30 June: US troops withdraw from Iraqi towns and cities
Minutes later a second bomb went off in the northern area of Shurta Arbaa, killing at least nine people and wounding 35.
There were also reports of a roadside bombing in the southern suburb of Saidiyah, killing at least two people and wounding 14.
This is the latest in a series of deadly blasts in Iraq since US troops pulled back from Iraqi cities at the end of June.
A car bomb exploded outside a mosque in Mosul during a funeral service last Friday, killing 30 people.
Three bombs killed six people returning from a pilgrimage in Baghdad on the same day.