BAGHDAD - A wave of attacks against Shiite Muslims killed at least 78 people on Thursday, the worst toll in nearly five months, as Iraq grappled with a weeks-long political row that has stoked sectarian tensions.

The violence, which wounded more than 100, comes two weeks after a crisis erupted when the Shiite-led authorities charged Sunni Vice-President Tareq al-Hashemi with running a hit squad soon after US troops pulled out.

The United States and the European Union swiftly condemned the attacks.

"We condemn these acts, we consider them acts of terror," US State Department spokeswoman Victoria Nuland said at a regular news briefing.

"They are desperate attempts by the same kind of folk who have been active in Iraq trying to turn back the clock," she added.

The EU top diplomat Catherine Ashton deplored the "death and destruction caused by these acts of terrorism, which can only exacerbate an already fragile political situation".

Ashton, who is the EU high representative for foreign affairs, called on all Iraqi political groups to engage in an "inclusive and genuine dialogue ... in order to address their differences".

Thursday's attacks were also quickly condemned by Iraq's parliamentary speaker Osama al-Nujaifi, a Sunni, as well as by Iraq's Shiite-majority neighbor Iran and UN special envoy Martin Kobler.

Shiite Prime Minister Al-Maliki met on Thursday with al-Nujaifi, a member of al-Hashemi's Iraqiya party. In televised comments afterward, they described the talks as positive and said they will work to find a way out of the crisis. Earlier, both men condemned Thursday's bombings.

Second major blasts

Targeted Shiite pilgrims and neighborhoods in the Iraqi capital city of Baghdad and southern Iraq, the series of bomb attacks on Thursday is the second large-scale assault by militants since US forces pulled out last month.

The worst incident saw at least 45 people killed by a suicide attacker on the outskirts of the southern city of Nasiriyah as pilgrims were walking to the shrine city of Karbala for Arbaeen commemorations.

"Hospitals in Nassiriya have received 45 killed and 68 wounded," said Hadi Badr al-Riyahi, head of the provincial health department in Dhi Qar, of which Nasiriyah is the capital.

Arbaeen marks 40 days after the Ashura anniversary commemorating the killing of Imam Hussein, one of Shiite Islam's most revered figures, by the armies of the Caliph Yazid in AD 680.

Five bombings also struck two Shiite neighborhoods of northern Baghdad, killing 23 people and wounding dozens.

In Kadhimiya, two car bombs exploded around 9 am local time at adjoining intersections, said interior and defense ministry officials.

The blasts killed 14 people and wounded 37 others, the defense official said, while the interior ministry source put the toll at 15 dead and 31 wounded.

In Sadr City, a booby-trapped motorcycle exploded at around 7 am near a group of day laborers waiting to pick up work, killing seven and wounding 20, the interior ministry official said.

A short time later, twin roadside bombs detonated near the district's main hospital as victims were being ferried in, killing two more people and wounding 15, the official said.

The violence on Thursday was the second major strike against Iraqis since a political crisis erupted last month. Two weeks earlier, militants killed at least 69 people as a wave of bombs ripped through mostly Shiite neighborhoods in Baghdad. An al-Qaida front group in Iraq claimed responsibility.

AFP-AP-Xinhua