Iraqi leaders are expected to begin complex talks on Tuesday over forming a government and allocating cabinet portfolios under new prime minister-designate Ali al-Zaidi.
Five months on from elections, Iraq remains deadlocked in negotiations over a new administration, after US pressure scuppered the choice for prime minister of the majority bloc in parliament.
Two-time ex-premier Nouri al-Maliki, who has close ties to Iran, had been endorsed by the bloc but was forced to step back after an ultimatum from US President Donald Trump.
Since the 2003 invasion of Iraq led by the United States, the country has walked a tightrope between the competing influences of Washington and Tehran.
On Monday, Iraq's new President Nizar Amedi nominated businessman Zaidi as prime minister-designate, giving him the daunting task of putting a cabinet together in the next 30 days amid fierce political wrangling.
The Coordination Framework -- the majority bloc in parliament and an alliance of Shiite groups with varying ties to Iran, had backed Maliki but appears to have yielded to the US pressure.
The framework has now endorsed Zaidi and thanked Maliki, a key member of their alliance, for dropping out.
Iraq's state-run INA news agency quoted a framework official late Monday as saying the alliance would meet on Tuesday with Zaidi to discuss the cabinet.
Zaidi said he is determined to work "with all political forces", INA reported.
Seen as a compromise figure, Zaidi, 40, is little known in political circles, and has never held a government post.
A businessman and owner of a television channel, he once headed one of the many Iraqi banks that are banned from conducting dollar transactions under US anti-money laundering regulations.
If Zaidi succeeds in forming a government, he will replace Mohammed Shia al-Sudani, who until recently enjoyed smooth relations with the US.
Sudani's hopes for a second term as prime minister faded after he failed to stop Iran-backed groups from targeting US interests during the Middle East war.
A political source told AFP that the Coordination Framework endorsed Zaidi "after checking" with US representatives.
Victoria J. Taylor, director of the Iraq Initiative at the Atlantic Council think tank, said on X that "the framework would not have nominated him without some sense that the US would accept his nomination".
Trump's "public opposition to Maliki was deeply embarrassing and the framework doesn't want to go down that road again," added Taylor, who is a former US deputy assistant secretary for Iraq.
Zaidi's nomination also emerged 10 days after an Iranian commander visited Iraq and met with political leaders.