"There were three car bomb explosions, two at 8:30 AM (05:30 GMT) and another 30 minutes later," said Nusayef Jassem, the provincial vice chief.
"Twelve people were killed and 150 wounded in the attacks," he said.
Dr Laith Sharifi, an official of the provincial health department, said earlier that 10 people were killed and 50 wounded, with women and children among the victims.
Another doctor said that of the wounded, 10 were in serious condition.
In other attacks across Iraq on Monday, gunmen killed two anti-Qaeda militiamen in the northern city of Kirkuk, while a roadside bomb in Baghdad killed a military officer. An intelligence official, two guards and eight civilians were wounded in explosions.
The two first car bombs targeting pilgrims exploded at a bus terminal at the Al-Ibrahimi area, 20 kilometres (12.5 miles) east of Karbala, Jassem said. The third exploded at the Al-Hindiya district, about three kilometres (two miles) from the site of the twin blasts.
Hundreds of thousands of Shiite pilgrims are descending on the city for Arbaeen ceremonies, held to mark 40 days since the anniversary of the death of the revered seventh century Imam Hussein, which climax on Tuesday.
Three car bombs last Thursday went off around 20 minutes apart on the outskirts of Karbala, killing 45 people and wounding 150.
One of the pilgrims, Jassem al-Zahra, 32, said that since cars were not allowed to enter inside Karbala for Arbaeen, he had parked on the outskirts to walk to the city on foot.
"I was in the parking lot, waiting for my friends and relatives with dozens of other pilgrims, among them women and children, when the explosion happened," he said.
"I was wounded in the arm, and saw many victims killed and wounded who were thrown to the ground," he said from his hospital bed.
Abdul al-Hor, 24, said he was on his way to the city on foot at about 9:00 am (0600 GMT) when an explosion threw him to the ground.
"I was near a car that exploded among a crowd of people, and only remember being thrown to the ground," he said at Karbala`s Al-Hindiya hospital, where he was being treated for head wounds.
The attacks come amid a surge of violence in Iraq, with blasts in the past week, which included suicide bombs, killing at around 130 people and wounding scores more.
By comparison, a total of 151 people were killed throughout December.
In Baghdad on Monday, a home-made bomb killed Brigadier General Thamer Hassan Saleh, who worked for services linked to the prime minister`s office, an interior ministry official said.
The bomb, detonated close to the general`s home in the Ghazaliyah district in western Baghdad, also wounded a member of the intelligence services.
In the Al-Shuala neighbourhood in northwestern Baghdad, eight people were wounded by an improvised bomb that exploded near a petrol station, the official said.
Another improvised bomb targetted a convoy transporting the governor of northern Salaheddin province Ahmed Abdullah Abid to work, the official said. He was unharmed, but two guards were wounded.
In the northern city of Kirkuk, meanwhile, gunmen killed two militiamen of the Sahwa (Awakening) forces that turned against Al-Qaeda and sided with the US military from late 2006, a police official said.
He identified them as Qatia Saad Jouri al-Obaiki, a Sahwa leader, and the other militiaman as Muhammed Fanar al-Obaidi, saying they were killed in a dawn attack at the al-Hameera village south of Kirkuk.
On Sunday, an Al-Qaeda front group in Iraq claimed responsibility for a series of suicide bombings north of Baghdad last week that cost more than 60 lives.
The Islamic State of Iraq (ISI), according to a US group which monitors Islamist websites, said its suicide bombers carried out the attacks in Baquba and Tikrit.
The attacks had targeted Iraqi security forces and the provincial council of Diyala, of which Baquba is the capital, that it said was attempting "to spread the Shiite doctrine" in the central Iraqi province. (*)
Editor: Kunto Wibisono
Copyright © ANTARA 2011