Anxious oil firms
They are anxiously awaited by foreign oil companies making plans to invest billions of dollars in Iraq and by Washington policymakers as the US prepares to formally end combat operations by the end of August and leave the country before 2012.
The IHEC results showed al-Maliki's State of Law coalition ahead with 124,734 votes in the two provinces with at least 30 per cent of votes counted, followed by 103,583 for a mainly Shia rival, the Iraqi National Alliance.
A secular, cross-sectarian list headed by Iyad Allawi, a former prime minister, got 40,916 votes. That list is expected to do well in Sunni areas in northern and western Iraq.
A clear victory by any of the blocs is unlikely and negotiations to form a coalition government could take months, leaving the possibility of a dangerous political vacuum.
Sixty-two per cent of Iraq's nearly 19 million voters turned out at the polls on Sunday despite death threats from the al-Qaeda-linked Islamic State of Iraq. A spate of election-day attacks left 39 people dead.
Al-Maliki's State of Law coalition, an alliance of his Dawa party and some Sunni tribal leaders, Shia Kurds, Christians and independents, led in Baghdad, the biggest electoral prize with about 8 million people, according to informal tallies.
State of Law was the big winner in the January 2009 provincial elections and campaigned on a platform of improved security and strong central government.
Even if al-Maliki and his allies make up the biggest bloc in Iraq's next parliament, they will have to unite with one or two other coalitions to form a government, and al-Maliki may face challenges from coalition partners opposed to giving him a second term.
Final results may take several weeks. Ad Melkert, the UN special representative to Iraq, lauded the vote count on Wednesday as an "honest process" and urged candidates and parties to accept the results.