Car bombs tore through a Najaf funeral procession and a main bus station in the nearby Shiite city of Karbala on Sunday, where at least 13 people were killed and 33 were wounded.
The deadliest attacks in Iraq since July were a bloody reminder that the Shiite heartland in the south — and not just the Sunni regions of central and northern Iraq — is vulnerable to the mainly Sunni insurgents aiming to wreck the country's key elections scheduled for Jan. 30.
In Baghdad, dozens of gunmen — unmasked and apparently unafraid to show their faces — executed three election officials on Sunday, part of their campaign to disrupt next month's parliamentary ballot. The gunmen ran rampant over a main downtown thoroughfare, dragged the three workers from a car, lay them on the street in the middle of morning traffic and shot them point-blank.
Together, the attacks appeared to be a calculated offensive against anyone in favor of Iraqi elections, reports CBS News Correspondent Kimberly Dozier.
The Shiites stand to gain the most political power in the upcoming polls - because they outnumber other ethnic groups about two-to-one.
In other developments:
Authorities in Najaf banned cars from entering the downtown area that houses the Imam Ali shrine to prevent future car bombings, Governor Adnan al-Zurufi said Monday.
"Fifty people, some of them from Najaf and others from outside, have been detained. One person detained this morning is a citizen of an Arab country. They are all being interrogated," al-Zurufi told reporters after taking part in a funeral procession attended by thousands of residents.
The deadly strikes Sunday highlighted the apparent ability of the insurgents to launch attacks almost at will, despite confident assessments by U.S. military commanders that they had regained the initiative after last month's campaign against militants in Fallujah.
Shiites, who make up around 60 percent of Iraq's population, have been strong supporters of the polls, which they expect will reverse the longtime domination of Iraq by the Sunni Arab minority. The insurgency is believed to include many Sunnis who have lost prestige and privilege since Saddam Hussein's fall.
Meanwhile, in a message passed on by lawyers who visited him in his cell last week, Saddam denounced the elections as an American plot.
"President Saddam recommended to the Iraqi people to be careful of this election, which will lead to dividing the Iraqi people and their land," Ziad al-Khasawneh, who heads Saddam's legal team, said in Jordan. An Iraqi member of the team met Saddam in detention on Thursday.
Saddam said the elections "aimed at splitting Iraq into sectarian and religious divisions and weakening the (Arab) nation," said Bushra Khalil, another member of the defense team.
The Najaf car bomb detonated in central Maidan Square where a large crowd of people had gathered for the funeral procession of a tribal sheik — about 100 yards from where Gov. al-Zurufi and police chief Ghalib al-Jazaari were standing. They were unhurt.
"A car bomb exploded near us," al-Zurufi said. "I saw about 10 people killed." Al-Jazaari believed he and al-Zurufi were the targets of the attack.
The Karbala blast destroyed about 10 passenger minibuses and set ablaze five cars outside the crowded Bab Baghdad bus station.
It was Karbala's second bombing in a week. On Wednesday, a bomb exploded at the city's gold-domed Imam Hussein Shrine, killing eight people and wounding 40 in an apparent attempt to kill a top aide to Iraq's most powerful Shiite cleric, Grand Ayatollah Ali al-Sistani.
"These operations aim at driving the Shiites away from the political process and toward acts of revenge to undermine the national unity," said Jalal Eddin al-Sagheer, an official with the leading Shiite political party, the Supreme Council for the Islamic Revolution. "The whole issue has to do with elections."
Grand Ayatollah Mohammed Said al-Hakim, one of Najaf's top four Shiite clerics along with al-Sistani, denounced the bombings, saying they aimed to "create a disturbance in security and incite sectarian sedition" and that God will "avenge and compensate" the victims.
The Baghdad ambush was the latest attack to target Iraqi officials working to organize the elections.
During morning rush hour, about 30 armed insurgents, hurling hand grenades and firing guns, swarmed onto Haifa Street, the scene of repeated clashes between U.S. forces and insurgents. They stopped a car carrying five employees of the Iraqi Electoral Commission and killed three of them. The other two escaped.
The commission condemned the attack as a "terrorist ambush."