Bomb attacks in mainly Shi'ite Muslim areas of Iraq killed at least 73 people and wounded scores on Thursday, police and hospital sources said, raising fears of an increase in sectarian strife, Reuters reported.
The biggest attack was beside a police checkpoint west of Nassiriya in the south, where a suicide bomber targeting Shi'ite pilgrims killed 44 people and wounded 81, Sajjad al-Asadi, head of the provincial security committee in Nassiriya, told Reuters.
Shi'ite Prime Minister Nuri al-Maliki created the worst political crisis in a year on December 19 when he sought the removal of two senior Sunni politicians, a day after the last U.S. troops left Iraq. On December 22, bombs in predominately Shi'ite parts of Iraq's capital killed 72.
Maliki asked parliament to have his Sunni deputy Saleh al-Mutlaq removed and sought the arrest of Sunni Vice President Tareq al-Hashemi on charges he ran death squads.
On Tuesday, members of the Sunni-backed Iraqiya bloc boycotted the parliament and cabinet, accusing Maliki's bloc of governing alone in a power-sharing coalition that was supposed to ease sectarian tension.
The inclusion of Iraqiya in the governing coalition was widely considered crucial to prevent a return to the level of sectarian violence that erupted after the 2003 U.S.-led invasion. Thousands were killed in the fighting.
The manager of the main hospital in Nassiriya, Ahmed Abdel-Sahib, put Thursday's toll at 44 killed and 88 wounded.
Photographs showed relatives hugging the bodies of young men lying face down on ground covered in blood and with the pilgrims' belongings strewn around them.
Hundreds of thousands of Shi'ite pilgrims are expected to make their way to the holy Shi'ite city of Kerbala in the south before Arbain, a major Shi'ite religious rite next week.
Earlier on Thursday, a bomb planted on a parked motorcycle and another roadside explosive device killed at least 10 people and wounded 37 in Sadr City, a slum district in northeast Baghdad, police and hospital sources said.
Police said they found and defused two other bombs.
"There was a group of day labourers gathered, waiting to be hired for work. Someone brought his small motorcycle and parked it nearby. A few minutes later it blew up, killed some people, wounded others and burned some cars," said a police officer at the scene, declining to be named.
A Reuters reporter said there was blood around the site of the motorcycle bomb attack and tarmac on the road had been ripped up by the blast. Building tools and shoes were scattered across the site.
Reuters TV video from Sadr City hospital showed a crowded emergency room with many injured people and their relatives. One man sat on the floor, hugging his younger brother, as they cried for their sister who was killed in one of the blasts.
Two car bombs in Baghdad's northwestern Kadhimiya district killed at least 15 people and wounded 32, police and hospital sources said.
"People started to flee from the explosions and others ran towards them (to look for relatives). The scene was like a play, with people crying and screaming and falling," Ahmed Maati, a policeman in Kadhimiya, told Reuters.
Iraq - on the brink of civil war as recently as 2006-7 - is still plagued by a Sunni Muslim insurgency and Shi'ite militias nearly 9 years after a U.S.-led invasion ousted Saddam Hussein.
Sadr City is a stronghold of radical Shi'ite cleric Moqtada al-Sadr, whose Mehdi Army militia once fought U.S. and Iraqi troops. He is now a key ally of Maliki.
Baghdad's health statistics department put the final toll from the Kadhimiya blasts at 16 killed and 36 wounded and said 13 were killed and 32 wounded in the Sadr City attacks.
"It is early to point our fingers to a particular side till we clarify some issues related to the investigations," said Baghdad operations centre spokesman Qassim al-Moussawi.
"We are in a battlefield with the terrorists ... and with the enemies of the political process, so we do not consider these (explosions) as a surprise for us or something strange. We are used to such (insurgent) operations."
Moussawi put the toll from the Sadr City attack at 33 wounded and said 29 were wounded in the Kadhimiya bombings. He said he did not have figures for the number of people killed.
Many Sunnis say they have been sidelined in the political process since Saddam was ousted and the majority Shi'ites dominated the government.