Iraqi President Fouad Massoum has named a new prime minister to end Nouri al-Maliki's eight-year rule, but Maliki is refusing to go after deploying special forces on the streets of Baghdad.
Speaking on state television Monday, Massoum said he hoped Haidar al-Abadi would succeed in forming a new government that would "protect the Iraqi people" and unify the country against the growing threat of radical Sunni militants.
But the president's public rejection of Maliki's bid for third term has raised the stakes in the fierce battle for political control.
Ibadi now has 30-days to form a new government that can win parliamentary approval.
However, Maliki accused Massoum of carrying out "a coup against the constitution and the political process."
Maliki's Shiite-dominated bloc won the most parliament seats in April's election.
U.S. President Barack Obama welcomed Massoum's decision.
He said it was an "important step" on a path towards a more inclusive government that will "unite Iraq's different communities."
"I urge all Iraqi political leaders to work peacefully through the political process in the days ahead. This new Iraqi leadership has a difficult task, The United States stands ready to support a government that addresses the needs and grievances of all Iraqi people."
On the battlefront, Kurdish forces continue their fight against Islamic State militants in the north and west of Iraq with the help of American airstrikes.
U.S. aircraft on Monday hit four militant checkpoints and destroyed several of the group's vehicles near Mount Sinjar, where thousands of people of the Yazidi religious sect have taken refuge.
Shin Se-min, Arirang News.