KERBALA, Iraq (Reuters) - A bomb killed at least 20 Shi'ite pilgrims on Wednesday as they poured into Iraq's holy city of Kerbala, triggering criticism of security forces and politicians before a potentially bloody March election.
The attack was the latest this week by suspected Sunni Islamist insurgents on Shi'ites making a religious trek to the city during a politically charged election period.
But in a move that may ease some sectarian tensions, an appeals panel agreed to allow candidates banned for ties to Saddam Hussein's outlawed Baath party to stand in the poll.
Police and hospital sources said Wednesday's bomb, which was planted in a cart pulled by a motorcycle, wounded up to 110 people in Kerbala, 80 km (50 miles) southwest of Baghdad.
Police said that a bomb attached to a military vehicle killed three people and wounded 21 others on Tuesday in Kerbala. On Monday, a female suicide bomber killed more than 40 pilgrims on the outskirts of Baghdad.
Sunni Islamist insurgents such as al Qaeda frequently hit Shi'ite gatherings with suicide bombers, grenades and shootings in the hope of re-starting bloody sectarian strife that nearly tore Iraq apart after the 2003 U.S.-led invasion.
Prime Minister Nuri al-Maliki has made improved security across Iraq a central theme of his campaign for the March 7 parliamentary election and he has called on the security forces to ensure pilgrims heading to Kerbala are protected.
The attacks on pilgrims and a series of coordinated suicide bombings in Baghdad since August could harm his efforts to claim credit for an overall drop in violence in the past two years and may be aimed at lowering his chances of re-election.
"These attacks are aimed at undermining Iraq's efforts to have a successful national election by throwing the country back into sectarian strife," political analyst Hazim al-Nuaimi said.
"Some regional countries want a weak Iraq to serve their interests," he added, echoing a widely held view that the beaten but still potent Sunni-led insurgency is funded by Arab nations while Shi'ite militia continue to be supported by Iran.
Tensions springing from the violence have been exacerbated by Sunni suspicions that a ban on candidates suspected of links to Saddam's Baath party was an attempt by Iraq's Shi'ite majority to sideline them in the poll.
Electoral officials said an appeal panel that ruled the nearly 500 banned candidates would be allowed to stand after all, potentially defusing the controversy that had threatened to reopen old sectarian wounds.
"The appeals panel decided to allow the banned candidates to participate in the next election and decided to postpone looking into the case until after the election," Hamdiya al-Husseini, a member of the Independent High Electoral Commission, said.
The candidates would not be able to assume office if they won until the panel gives a final ruling, she said.
Sunni lawmaker Saleh al-Mutlaq, who is on the list, called the decision a "victory" for the Iraqi people. But Mohammed al-Nasiri of Maliki's Shi'ite Dawa party said: "This is a very bad thing ... This resolution is rejected, and the Baathists and their supporters cannot participate in the election."
Iraq is trying to leave behind years of sectarian carnage, war and mayhem. It is starting to revamp a dilapidated oil sector that provides Iraq with nearly all its revenues.
Pilgrims in Kerbala blamed politicians and security forces.
"Some parties are trying to undermine Maliki's security triumphs to bring voters over to their side," said Subhi Naji, 35, an unemployed engineer. "I expect attacks will mount ahead of the election to take advantage of the failure of security forces to do their job professionally."
Officials said 30,000 troops and police were in Kerbala for the Arbain rite, marking 40 days of mourning for Hussein, the Prophet Mohammad's grandson, who died in the seventh century.
"We will never bow to terrorists. Today I'm coming to Kerbala to practice my rituals and soon I will vote with same determination," said Jasim Mohammed, a civil servant.
Additional reporting by Ahmed Rasheed and Aseel Kami; Writing by Jack Kimball; Editing by Michael Christie