Three bombs exploded in a market in Iraq's southern oil city of Basra on Thursday, killing at least ten people and wounding dozens, security sources said.
Basra, 420 km (240 miles) southeast of Baghdad, is the largest city in the mainly Shi'ite south and the heart of Iraq's oil industry. It hosts a major conference for international oil executives and industry officials starting on Friday.
Two bombs hidden in a three-wheeled motorbike exploded in quick succession at the market in northern Basra, and a third bomb went off a short time later as people gathered at the scene, two police sources said.
Noufal Hassan, the owner of a mobile phone shop near the scene, said he heard two explosions at the "Thieves Market".
"I immediately went out of my shop and saw the blood ... limbs, hands and legs, bodies spread on the streets," he said.
"The nearest shops were shattered and the cars were burned."
The blasts underscored Iraq's tenuous security situation as the remaining 18,000 US troops leave by year-end, nearly nine years after the invasion that toppled Saddam Hussein.
Iraqi officials have said militants may step up attacks as US troops withdraw.
Iraq is still plagued by a lethal Sunni Muslim insurgency and Shi'ite Muslim militias that carry out scores of bombings and other attacks each month.
Basra's four-day oil conference is expected to host senior government oil officials and executives from international companies such as Exxon Mobil and Royal Dutch Shell.
Hospital sources put the Basra bomb toll at ten dead and about 55 wounded, while a police source said 12 people were killed and 42 wounded.
Most of the victims were police and soldiers, including several senior leaders, said Ali al-Maliki, head of the Basra provincial council security committee.
"The fingerprints of Baathists and al Qaeda are clear in these explosions," he said.
Iraqi government officials frequently accuse former members of Saddam Hussein's banned Baath Party of trying to destabilise Prime Minister Nuri al-Maliki's fragile coalition government.
The government recently rounded up more than 600 former military leaders and Baathists, accusing them of plotting to seize power when US troops leave.
In the city of Ramadi, in western Anbar province, a bomb exploded in a crowded market, wounding five people, police said.