BAGHDAD (AP) — An influential Shiite preacher who heads a powerful political bloc in Iraq’s Parliament threatened Tuesday to withdraw support for the candidate chosen by rival blocs as prime minister designate, indicating the formation of a new government was facing challenges.

Muqtada al-Sadr, who heads the Sairoon bloc that garnered the most seats in parliament following the May 2018 election, said in a statement posted on social media that he was losing confidence in prime minister designate Mohammed Allawi and threatened to withdraw his support.

Citing “partisan and sectarian pressure” interfering in the government formation process, al-Sadr said this has lead to a “lack of confidence” and “may even lead to declaring a disavowal” of Allawi’s candidacy.

Allawi, like his predecessor Adel Abdul-Mahdi, was a compromise candidate of rival blocs Sairoon, and Fatah, which includes leaders associated with the paramilitary Popular Mobilization Units headed by Hadi al-Amiri.

In the May 2018 election, neither coalition won a commanding plurality that would have enabled it to name the premier, as stipulated by the Iraqi constitution. To avoid political crisis, Sairoon and Fatah forged a precarious union with Abdul-Mahdi as their prime minister. On Feb. 1 they chose Allawi to succeed Abdul Mahdi, after he resigned under pressure from protests in December.

Allawi has 30 days to formulate a government program and name Cabinet ministers. Iraq’s constitution requires that each candidate will have to be voted in by parliament. That effectively means both Saeroon and Fatah will have to consent to Allawi’s Cabinet lineup.

Al-Sadr’s statement signaled the process was not going smoothly.

The radical cleric also said he was dissolving the “blue hats,” a nickname for his militia group in the Iraq’s anti-government protest sites in Baghdad and parts of southern Iraq. Members of his group are known to man checkpoints unarmed and are distinguished by blue caps.

The statement came one week after followers of al-Sadr stormed a protest site in the southern city of Najaf and fired live bullets, killing eight anti-government demonstrators.

Al-Sadr initially threw his weight behind the anti-government uprising but recently re-positioned himself toward the political establishment after political elites selected Allawi as prime minister-designate, a candidate he endorsed.

Since then, al-Sadr has issued a dizzying array of calls to followers, asking them to return to the streets days after withdrawing support from protests. The contradictory orders have exacerbated existing tensions between anti-government demonstrators and his followers.