Iran Press/Middle East: Abdel Mahdi said the justice system "must do its job and the investigation must produce results on the reasons for this shipwreck".
He and Iraqi President Barham Saleh visited the site of the accident as the search continued for bodies, some of which were carried far downstream by the strong current.
Iraq's justice ministry said it had ordered the arrest of nine ferry company officials and banned the owners of the vessel and the tourist site from leaving the country.
Dozens killed as a ferry overloaded with people celebrating the new year and Nowruz, sank in Tigris river near Mosul.
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Dozens killed as ferry sinks in Iraq's Tigris river
