At least 15 people have been killed and more than 30 injured after a suicide car bomb attack at a busy market in the Shia district of Sadr City.
The UN has warned of a looming human rights crisis in Kirkuk
The attack came hours after at least seven policemen and civilians died when a lorry exploded near a police station in the northern city of Kirkuk.
The violence follows a day of bloodshed in Baghdad, where at least 70 people were killed in a university bombing.
More than 34,000 Iraqis were killed in 2006, according to UN figures.
The UN death toll is more than three times the estimates by the Iraqi government.
In other developments:
- Three foreigners - an American, a Hungarian and a Croatian - as well as an Iraqi working for US non-governmental organisation the National Democratic Institute were killed when their convoy was ambushed in Baghdad, the NDI announced
- Two US soldiers are killed in western Iraq's Anbar province, the military reports
- US Senator Hillary Clinton says she is planning to write to US Defence Secretary Robert Gates, insisting that he reorder priorities in the region
- Three top US senators - including Chuck Hagel from President George W Bush's Republican party - introduce a resolution opposing the president's newly-announced plan on Iraq
'A broader war'
The explosion in Sadr City occurred at 1555 (1255 GMT) near the outdoor Mereidi market, one of the neighbourhood's most popular commercial centres, police said.
The force of the blast shattered windows of nearby stores and restaurants.
Earlier on Wednesday, at least seven people were killed and 25 injured in a lorry bombing in the oil-rich city of Kirkuk.