Many of the dead were women and children who could be seen struggling to swim against a strong current, their heads bobbing in the water opposite restaurants and an amusement park where people had been celebrating minutes earlier.
An Interior Ministry official said 94 people were killed in the accident, which residents said was the worst in recent memory. The official spoke on condition of anonymity in line with regulations. Col. Hussam Khalil, head of the Civil Defense in Iraq's northern Nineveh province, told The Associated Press the accident occurred as scores of people were out in the tourist area, known as Ghabat, celebrating Nowruz, which marks the Kurdish new year and the arrival of spring.
The boat had been ferrying people to a small island nearby. Abdulrazzaq Falih, a rescuer with the river police of Mosul, said he pulled more than 20 bodies from the water. "Children, women, and young, what can I tell you? It was a difficult situation," he said.
A man who identified himself as Abdul-Jabbar al-Jbouri appealed for the police to look for his wife and children. "My wife and three daughters are in the water!" he screamed. Mosul was devastated by the war against the Islamic State group, which occupied the city for three years. Iraqi forces drove the militants from Mosul in 2017 after a grueling campaign that left entire neighborhoods in ruins, and residents are still struggling to rebuild.
Videos of the ferry disaster posted online showed people struggling against the strong current. Young men who had been lunching on the banks jumped into the water with their clothes on to try and save people.
The usually tame Tigris is running high this time of year, fed by snowmelt from mountains in Turkey. The river swelled further after a rainy season that brought more precipitation than in previous years.
Falah al-Taii, director of Nineveh health department, said the number of victims that arrived at the forensic department and in the hospitals in Mosul is more than 60, the majority of them women and children.
"There is a large number of fathers and mothers who are looking for their children until now," he added. Khalil said the ferry sank because of a technical problem, and that there weren't many boats in the area to rescue people. He said more than 80 people were on the ferry when it sank. Others said the number of people on the boat was much higher.
Saudi Aziz, a 23-year-old Kurd, said he was on another ferry crossing the river. He said the stricken ferry was overloaded with around 150 people when it capsized. He said it wasn't long before he saw people drowning, their heads bobbing up and "sliding away across the water like plastic bags."
He said he jumped in the water and managed to save a 20-year-old girl. "I cannot describe the scene, it's a catastrophe," he said. Iraqi Prime Minister Adel Abdul-Mahdi ordered an investigation and, according to Iraqi TV, arrived in Mosul later Thursday, where he declared three days of national mourning.
The TV said nine workers operating the ferry have been detained and an arrest warrant is out for the owner of the tourist island where it was headed. The U.S. Embassy said Chargé d'Affaires Joey Hood and the entire mission "express our deepest condolences to the families and friends of those who lost their lives in the tragic ferry accident on the Tigris River near Mosul."
Nowruz, or the Persian new year, dates back to 1700 B.C. and incorporates Zoroastrian traditions. It is celebrated across territories that once made up the ancient Persian empire, stretching from the Middle East to Central Asia. Thursday was also Mother's Day in much of the Middle East.
Abdul-Zahra reported from Baghdad.