The latest explosions struck Thursday morning near Dujail, 80 kilometers (50 miles) north of Baghdad, as the pilgrims were heading to a shrine in the town of Samarra.
Raed Ibrahim, the head of the Salahuddin provincial health directorate, provided the death toll and says more than 60 were wounded.
Earlier, another car bomb killed four Shiite pilgrims as they were heading to shrines in the country's south.
Shiite pilgrims are a favorite target for Sunni insurgents who seek to undermine the country's Shiite-led government.
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