NAJAF (AFP) - A car bomb targeting pilgrims killed three people in Iraqs holiest city Saturday on the eve of the countrys parliamentary election which Al-Qaeda has threatened to wreck. The blast near a shrine in Najaf, which officials said killed two visiting Iranians and an Iraqi and wounded at least 54 people, came despite a massive nationwide security operation in the run-up to Sundays vote. It gutted four pilgrim buses, mangled cars and left the area spattered with blood, smashed glass and torn clothes, and blew out the windows of nearby hotels that host the thousands of Iranians who flock there every month. We had gathered all the pilgrims in the car park, and they were getting into the buses when the explosion took place, and killed and injured many visitors, said Hussein Banahi, an Iranian tour guide. Thirty-seven of the wounded were Iranians, officials said, adding the blast was just 500 metres from Najafs shrine of Hazrat Ali (RA). The attack carries the prints of Al-Qaeda and Saddamists, said Faed Al-Shimmary of the provincial council in Najaf, which lies south of Baghdad. Iranian Foreign Ministry spokesman Ramin Mehman-parast condemned the attack as an inhuman and criminal act. The final days of campaigning for Sundays polls, the second parliamentary ballot since US-led troops ousted dictator Saddam Hussein in 2003, have been overshadowed by a series of suicide bombings in Baghdad and the city of Baquba. The Islamic state of Iraq, the Al-Qaeda front here, said in a statement Friday it was imposing a curfew on Sunday and anyone who dared defy it would expose himself to the anger of Allah and... all kinds of weapons of the Mujahideen. Some 200,000 Iraqi police and soldiers will be on duty in Baghdad alone to provide security for the vote, the countrys borders and its airports will be shut for the day and all cars banned from the streets. Lt-Gen Charles Jacoby, the second highest-ranking US officer in Iraq, described the security operation as an all-Iraq show requiring little American manpower. Iraqi religious leaders used Friday prayers in mosques to order citizens to vote and safeguard democracy. Prime Minister Nuri al-Maliki, the Shia head of the State of Law Alliance, boasted this week he was certain of victory. But he faces stiff competition from Shia former premier Iyad Allawi, whose secular Iraqiya list has strong support in Sunni areas. Also competing for the top job are former deputy premier Ahmed Chalabi, who was once favoured but is now loathed by Washington, Shia Vice-President Adel Abdel Mahdi and Finance Minister Baqer Jaber Solagh. Iraqs fragmented political scene virtually ensures that no single party will emerge with the 163 seats needed to form a government on its own and the ensuing horse-trading to form a governing coalition is likely to be protracted. One thing that is almost certain is that the new prime minister will be from the Shiite majority that was oppressed by the Sunni dictator Saddam but which now dominates the political scene. The US military sees Sundays poll as a crucial precursor to withdrawing its combat troops by September. It says that after that date it hopes to have only 50,000 soldiers here. Currently there are about 96,000 US troops in the country but they are mostly confined to their bases under the terms of a security agreement that saw them leave Iraqs cities, towns and villages in June last year.