BAGHDAD -- Separate suicide bombings ripped through busy commercial areas in Shiite-dominated neighbourhoods of the Iraqi capital on Tuesday, killing at least 17 civilians, officials said.

The deadliest attack took place in the eastern New Baghdad neighbourhood, where a bomber approached a gathering of construction workers and set off his explosives-laden vest, killing 11 civilians, a police officer said. At least 28 civilians were wounded and the explosion damaged nearby shops and cars, he said.

Hours later, another suicide bomber blew himself up in an outdoor market in the southwestern neighbourhood of Bayaa, killing six shoppers and wounding 21 others, another police officer said.

Medical officials confirmed the casualty figures. All the officials spoke on condition of anonymity as they were not authorized to release the information.

In online statements, the Islamic State group claimed responsibility for the attacks, saying it targeted Shiite militia members. The Associated Press could not verify the authenticity of the statements, but they were posted on a militant website commonly used by the extremists.

The militants, who control parts of Iraq, have recently relied on insurgency-style attacks away from front lines as they suffer losses on the battlefields. The biggest urban area they control in Iraq is the country's second-largest city of Mosul, about 225 miles (360 kilometres) northwest of Baghdad. Iraqi officials have said they plan to retake the city by the end of the year.