Iraq ramped up security on Friday on the eve of its first election since US troops left, as attacks, including a bombing at a Baghdad cafe, killed 37 people in a spike in unrest before polling day.
The deadly violence just before Saturday's provincial election raises further questions about the credibility of the polls, with 14 candidates killed and a third of Iraq's provinces -- all of them mainly Sunni Arab or Kurdish -- not even voting.
The election is seen as a key test of Iraq's stability and security, and will provide a gauge of the popularity of the Shiite-led government of Prime Minister Nuri al-Maliki ahead of a general election next year.
But attacks on Thursday and Friday that left 37 dead increased concerns about the ability of Iraqi forces to assure security for the polls.
On Thursday evening, a bomb in the west Baghdad suburb of Amriyah killed 27 people and wounded more than 50, officials said.
Further attacks in the capital and northern Iraq on Friday killed another 10 people and wounded dozens more.
The Baghdad blast on Thursday hit a billiards cafe frequented by young men inside a small shopping mall on the main road in the predominantly Sunni Arab neighbourhood.
Witnesses said it wreaked massive damage.
Security forces restricted access to the area, but the tightened searches did little to placate anger in Amriyah, where many residents accused authorities of negligence.
"If it was not them (soldiers) who did it, it was their fault," said one resident who declined to be named.
"We are surrounded by walls and checkpoints, so if it's not them who did it, they helped because they were lazy or they did not perform the checks well."
On Friday, four mortar rounds struck near a Sunni mosque as worshippers left noon prayers in the restive town of Khalis, killing seven and wounding 12, while a bomb detonated at a Shiite mosque in Kirkuk at around the same time, leaving one dead and 15 wounded.
A civil servant was shot dead in Baghdad, and a soldier was killed and 14 people wounded by several roadside bombs in and around the main northern city of Mosul.
The attacks all took place despite heightened security nationwide ahead of Saturday's election.
Movement is expected to be tightly controlled on Saturday, with only approved vehicles allowed on the streets and concertina wire closing off areas around polling stations. Some restrictions were already in place ahead of the vote.
"We will use all of our forces in the interior and defence ministries to control the situation," said interior ministry spokesman Brigadier General Saad Maan.
The latest deaths bring to 120 the number of people killed since Sunday, an average of 20 per day, according to AFP figures.
No group immediately claimed responsibility for the attacks, but Sunni militants linked to Al-Qaeda often carry out bombings in both Sunni and Shiite neighbourhoods across Iraq, in a bid to undermine confidence in the Shiite-led government and security forces.
An estimated 13.8 million Iraqis are eligible to vote for more than 8,000 candidates, with 378 seats being contested.
It is the first vote since March 2010 parliamentary polls, and the first since US forces withdrew from Iraq in December 2011.
Diplomats have raised questions over the credibility of the vote due to the violence, which they say could reduce turnout and lead to results that are not representative.
Attacks against candidates have already left at least 14 dead and led others to withdraw for fear of being targeted.
Six of Iraq's 18 provinces will not be taking part -- three in the autonomous Kurdish north, the ethnically divided province of Kirkuk, and two mainly Sunni Arab provinces where authorities say security cannot be ensured.
Iraqi forces will be responsible for security on polling day, the first time they will be in charge without support from American or other international forces during elections since dictator Saddam Hussein was toppled in 2003.