Karbala bombs kill dozens during Shia commemorations
Two bomb attacks near the Iraqi city of Karbala have killed at least 50 people and injured more than 150, officials say.
The blasts happened on two routes being used by pilgrims taking part in the Shia Muslim commemorations of Arbaeen.
Earlier, a suicide bomber killed at least three people in the central city of Baquba - the second deadly attack in the city in as many days.
Violence in Iraq has reduced in recent years, but attacks continue.
Thursday's bombings occurred near police checkpoints controlling the northern and southern entrances to Karbala.
Hundreds of thousands of pilgrims are converging on the city from all over the country for the Arbaeen commemorations, which reaches its climax next week.
The sudden flare-up of violence over the past three days is bad news for the fledgling Iraqi government, for several reasons.
Draconian security measures had been put in place for the annual Arbaeen pilgrimage which sees many hundreds of thousands of Shias walking to the city from all over the country. Yet once again dozens have been slaughtered along the way.
Suicide bomb attacks on Iraqi security centres in Tikrit on Tuesday and Baquba on Wednesday, both north of Baghdad, had already raised fears that the tempo of violence was picking up.
This upsurge comes at a time when Iraq is trying to persuade Arab leaders that it is safe to come here in March, when Baghdad is preparing to host a full-scale Arab summit meeting for the first time in 20 years.
The BBC's Jim Muir in Baghdad says the authorities were well aware of the dangers, as previous pilgrimages have been attacked.
Strict security measures are in place, but protecting vast numbers of people travelling on foot over large areas has proven exceptionally difficult, our correspondent says.
The dead include women and children, medical sources at Karbala hospital say.
A witness to one of the attacks, named as Khamas, told the Associated Press news agency: "After the explosion, people started to run in all directions, while wounded people on the ground were screaming for help."
However, he added that pilgrims would continue to head to Karbala: "It will not deter us from continuing our march to the holy shrine... even if the explosions increase."
No group has said it carried out the Karbala bombings, but correspondents say they bear the hallmarks of Sunni militants.Police targeted
Adil Barwari, an aide to Prime Minister Nouri Maliki, told AP that the attacks showed the militants' determination "to undermine the new Iraqi government".
The government, which includes the country's major political factions, was approved by MPs last month, ending nine months of post-election deadlock.
The Karbala attacks came hours after a suicide bomber blew up his car outside police headquarters in Baquba, killing three and wounding about 30.
On Wednesday another suicide bomber in the city targeted a police compound, killing 14.
And on Tuesday in Tikrit, the home town of former Iraqi leader Saddam Hussein, a suicide bomber joined a queue of about 100 police volunteers and killed about 60 of them.
US forces formally ended their combat operations last August, ahead of a planned full withdrawal later this year.