The attacks illustrate how difficult it will be to hold elections scheduled for January 30, reports CBS News Correspondent Cami McCormick.
The bombings came just over an hour apart — first a suicide blast that ripped through minibuses at the entrance of the main bus station in the city of Karbala, then a car bomb in a central square of Najaf crowded with people watching a funeral procession attended by the city police chief and provincial governor.
The violence was the latest in an insurgent campaign to disrupt the crucial Jan. 30 elections, the first national polls since the fall of Saddam Hussein — and they were the latest attacks to target Shiite Muslims, the majority community in Iraq and the most likely to dominate the vote.
The car bomb in Najaf 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. Adnan al-Zurufi and police chief Ghalib al-Jazaari were standing.
Youssef Munim, head of the statistics department at Najaf's al-Hakim Hospital, said 47 people were killed by the explosion and 69 were wounded.
The nearby al-Zahraa Hospital received another two people killed by the bombing, plus 21 suffering from various injuries, according to nurse Mohanad Abdul Redha.
"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, in which he said three explosives went off at about 2:45 p.m. Both men were unhurt. "As I and the governor were waiting for the funeral processions three explosions occurred," al-Jazaari said. "We were targeted." It was not immediately clear what the other explosions were from.
Residents were pulling bodies of the dead from damaged shops at the square, which is about 400 yards from the Imam Ali Shrine, the holiest Shiite site in Iraq.
The bombing in Karbala, about 45 miles northwest of Najaf, destroyed about 10 passenger minibuses and set fire to five cars outside the crowded bus station. Firefighters tried to put out the blazes as ambulances ferried burned and bleeding casualties to the nearby al-Hussein hospital.
Ali al-Ardawi, assistant for the hospital's director, said 13 people were killed in the attack and 30 injured.
It was the second bombing in Karbala in a week. On Wednesday, a bomb went off 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.
The shrine, located near the bus station, was hit by a March 2 suicide bombing that killed 85 people and wounded 100. The holy sites in Najaf and Karbala, south of Baghdad, house the tombs of Shia Islam's most revered saints.
In Baghdad, two mortar rounds struck a hardline Sunni Muslim mosque, wounding four security guards, according to a religious leader associated with the mosque.
The 7 a.m. attack shattered large windows in the Um al-Tuboul mosque, sending up plumes of smoke.
Insurgents on Sunday also carried out a new attack on election officials, with a daylight assault on Baghdad's central Haifa Street, the scene of repeated clashes between security forces and insurgents.
About 30 militants hurling hand grenades and firing machine guns attacked a car carrying five people employed by the commission's Baghdad office and tried "to drag them out," said Adel al-Lami, a member of the Independent Electoral Commission of Iraq.
Three employees, including a security guard, were killed, while two escaped unhurt, he said.
A police official said four people were killed, adding that the ferocity of the clashes prevented police from nearing the area.
Witnesses said the attackers later set fire to the vehicle and wandered the street brandishing their weapons. U.S. and Iraqi National Guard forces cordoned off the area after the attacks, they said. A U.S. military spokesman had no immediate details.
Also, insurgents claiming to represent three Iraqi militant groups issued a videotape showing what they said were 10 abducted Iraqis who had been working for an American security and reconstruction company.
Masked insurgents in the video said they represent the Mujahedeen Army, the Black Banner Brigade and the Mutassim Bellah Brigade, all previously unknown groups. Nine blindfolded hostages could be seen lined up against a stone wall and a 10th was lying in a bed, apparently wounded.
The militants said they would kill the hostages if the company, Sandi Group, does not leave the country. They also threatened more attacks on its Iraqi operations.
Chad Knauss, an American and deputy chief operations officer of Sandi Group in Iraq, declined to comment on the claims. The company, based in Washington, employs 7,000 in Iraq.
Meanwhile, Iraqi police said they detained 45 men who illegally entered from neighboring Iran. The men were detained Saturday at Mandali, a border town 60 miles east of Baghdad. They had no identity documents but claimed to be Muslim pilgrims from Iran, Afghanistan or Bangladesh.
Also Sunday, a diplomat said two Egyptians employed by the Egyptian-owned mobile phone company Iraqna who were detained earlier this week by Iraqi and U.S. troops were released.
When asked why the men were seized from their Baghdad home on Wednesday, Farouk Riyadh Mabrouk, head of the Egyptian diplomatic mission in Baghdad, said only, "It was a big misunderstanding." U.S. and Iraqi authorities have not commented on why the men were detained.