Explosions killed 24 people as Iraqis voted on Sunday in an election that Sunni Islamist militants have vowed to disrupt, in one of many challenges to efforts to stabilise Iraq before US troops leave.

Scores of mortar rounds, rockets and roadside bombs exploded near polling stations in Baghdad, and some elsewhere, in a coordinated campaign to wreck the voting for Iraq's second full-term parliament since the 2003 US-led invasion.

Iraq's political course will be decisive for President Barack Obama's plans to halve US troop levels over the next five months and withdraw entirely by end-2011. It will also be watched by oil companies planning to invest billions in Iraq.

In the deadliest attacks, 12 people died when a bomb blew up a Baghdad apartment block and four were killed in a similar explosion at another residential building. A Katyusha rocket killed four people elsewhere in the capital of seven million.

At least 65 people were wounded around the country.

The Baghdad security spokesman, Major General Qassim Al-Moussawi, said most of the rockets and mortar bombs had been fired from mainly Sunni districts in and around the city.

'We are in a state of combat. We are operating in a battlefield and our warriors are expecting the worst,' he said.

Despite the hail of attacks, Al-Moussawi said a car ban aimed at foiling vehicle bombs had been lifted after less than four hours of voting. Curbs on buses and trucks stayed in force.   

The Islamic State of Iraq, an Al Qaeda affiliate, had warned Iraqis not to vote and vowed to attack those who defy them. The 96,000 US troops still in Iraq stayed in the background, underscoring the waning American role in Iraq.

Voters in the ethnically and religiously divided country can pick between mainly Shi'ite Islamist parties that have dominated Iraq since Saddam Hussein's fall and their secular rivals.   

Prime Minister Nuri Al-Maliki, a Shi'ite, urged all parties to accept the election results. 'He who wins today may lose tomorrow, and he who loses today may win tomorrow,' he said after casting his ballot in the fortified Green Zone enclave.

One of Al-Maliki's opponents, ex-Prime Minister Iyad Allawi, has already complained of irregularities in early voting. Allawi's secular list is tapping into exasperation with years of conflict, poor public services and corruption, and hopes to gain support from the once dominant Sunni minority.
   
About 6,200 candidates from 86 factions are vying for 325 parliamentary seats. No bloc is expected to win a majority, and it may take months to form a government, risking a vacuum that armed groups such as Iraq's Al Qaeda offshoot might exploit.  -Reuters