A bomb has killed dozens of Shiite pilgrims near the southern Iraqi port city of Basra.
The governor of Basra province's spokesman Ayad al-Emarah said it was not clear whether the blast near a shrine close to the town of Zubair was caused by a suicide attacker or a roadside bomb.
The attacks come as Shiites commemorate the climax of Arbaeen, which marks the end of 40 days of mourning following the anniversary of the death of Imam Hussein, a revered Shiite figure.
An Iraqi health official later said the death toll had risen to 53.
The head of the Basra provincial health directorate, Dr Riyadh Abdul-Amir, said hospitals received 53 killed and 137 wounded people after the blast. He said some of the wounded are in serious condition and warned the death toll may rise further.
The explosion was the latest in a series of attacks during Shiite religious commemorations that threaten to further increase sectarian tensions.