At least 140 people were feared killed and hundreds injured on Tuesday in a series of blasts at Shiite shrines in two Iraqi cities.

However, owing to the confusion, the exact toll in the blasts in capital Baghdad and the Shiite holy city of Karbala is not yet known.

In Baghdad, a CNN journalist reported piles of bodies stacked onto pickup trucks. A video from the scene showed blood-soaked streets littered with body parts, bodies burning and pilgrims running in panic.

The attacks occurred on Ashura, the 10th day of Moharram, when thousands of Shias gather to mourn the killing 13 centuries ago of Imam Hussein, the grandson of Prophet Mohammed.

Ashura is the holiest day in the Shiite calendar. Former president Saddam Hussein had not allowed Shias to mark the event for more than 30 years.