Iraqi lawmakers said on Thursday that deadlock in parliament was holding up the selection of an interim prime minister, meaning leaders would miss a deadline to name a replacement for Adel Abdul Mahdi and prolong nationwide unrest.More than 450 people, mostly unarmed demonstrators but also some members of the security forces, have been killed since a wave of popular unrest began on Oct. 1. Protesters, most of them young, are demanding an overhaul of a political system they see as profoundly corrupt and keeping most Iraqis in poverty.The protests have shaken the country out of two years of relative calm following the defeat of Islamic State insurgents.Infighting between political parties who are clinging onto power has fueled the crisis and threatens to cause more unrest as protesters lose patience.Prime Minister Adel Abdul Mahdi resigned last month under pressure from the streets but has remained in office in a caretaker capacity. The constitutional deadline to name a replacement expires on Thursday."Until this moment no candidate has been agreed on by the political parties. We have multiple nominees but their partisan affiliations prevent them from having the job," said Shi'ite Muslim lawmaker Naeem al-Abboudi.Two blocs of political parties, one backed by Iran and the other populist and anti-Iranian, are closely involved in backroom deals to agree on a candidate before Salih presents them.President Barham Salih this week asked the largest bloc in parliament to nominate a new premier to form a government. The two main blocs dispute who has the most seats because this was never made clear in the current parliament, and some lawmakers have frequently switched allegiance.“Differences are everywhere and it will not be easy to agree soon on a new election law inside parliament,” said Hassan Khalati, another Shi’ite lawmaker.Lawmakers and politicians said Salih could now delay the nomination to Dec. 22, based on a federal court ruling allowing national holidays to be excluded from the run-up to the constitutional deadline.That would create breathing space for the political factions to strike a deal, with Abdul Mahdi remaining as caretaker premier until then, legal expert Tareq Harb said.But any agreement on thorny political issues looks unlikely.The house failed on Wednesday to pass a new electoral law, a key demand of protesters, which would make elections fairer after each round in recent years has been marred by allegations of fraud.Protesters demand a new electoral law and committee, but also the removal of the entire political class, and a prime minister with no party affiliation.