BAGHDAD (AFP) - Prime Minister Nuri al-Maliki, a Shiite who helped ease sectarian strife, emerged on Monday as the front-runner in Iraq's parliamentary election but could yet face a tough battle to cling to power.

Maliki polled well according to early forecasts from Iraq's second election since the 2003 ouster of Saddam Hussein that saw millions defy bomb, mortar and rocket attacks which killed 38 people to cast ballots.

President Barack Obama, who has promised to withdraw all US troops from Iraq by the end of next year, paid tribute to "the courage and resilience of the Iraqi people who once again defied threats to advance their democracy."