Three bombs exploded in a busy market in Iraq's southern oil city of Basra on Thursday, killing at least 19 people and wounding 65.
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.
The first bomb was hidden in a three-wheeled motorbike and the others exploded after security forces arrived at the market, where vendors sell used motorbikes, mobile phones, construction material and other goods.
"The death toll is 19 killed and 65 wounded," said Riyadh Abdul-Amir, director-general of the Basra health department.
A police source put the toll at 20 dead and 65 wounded.
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 before the year-end departure of the last of the remaining 18,000 U.S. troops, nearly nine years after the invasion that toppled Saddam Hussein.
Iraqi officials have said militants may step up attacks as U.S. troops leave.
Iraq is still plagued by a 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.
Basra was hit by a triple bombing on Nov. 2 when explosions struck three cafes on a central street. At least 12 people were killed and 70 wounded.
Most of the victims of Thursday's bombing 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 U.S. troops leave.
In the city of Ramadi, in western Anbar province, a bomb exploded in a crowded market, wounding five people, police said.