The political coalition of influential Shiite cleric Muqtada al-Sadr took an early lead in Iraq's national elections in partial returns announced late Sunday by the Iraqi electoral commission.
Unlike Abadi, a rare ally of both the United States and Iran, Sadr is an opponent of both countries, which have wielded influence in Iraq since a US -led invasion toppled Sunni dictator Saddam Hussein in 2003 and thrust the Shiite majority into power.
Iraqi firebrand political figure Muqtada al-Sadr is set to be announced the surprise victor of the country's elections and prepared for his new status as government titan by making a call for national unity.
Sadr is an Iraqi nationalist who opposes both the US and Iran meddling in Iraqi affairs.
Sadr fled to Iran before a government crackdown on the Mehdi Army, but has since moved to distance himself from Iran.
On Tuesday, the prime minister called Sadr to congratulate him for the election victory, the cleric's office said.
Voter turnout was at a low 44 percent, 15 percent lower than the turnout in the 2014 parliamentary elections. The Iranian-backed Shi'ite militia chief Hadi al-Amiri came in second with about 1.2 million votes and will control 47 seats.
It may be Abadi, Reuters reports, who has signaled a willingness to work with Sadr to form a working government.
Reuters could not independently verify the document's authenticity but the results in it for the 16 announced provinces were in line with those announced by the commission. Of more than 2 million Iraqis displaced by the war, the majority are Sunnis.
At elections in 2010, the Iraqi National Movement of Ayad Allawi - loathed by Iran - scooped 91 seats to become the biggest group in parliament.