Sixteen Shiite pilgrims on their way by foot to a shrine city in central Iraq were killed on Monday when a female suicide bomber blew herself up at a rest station in Baghdad, security officials said.
At least 38 pilgrims were injured in the blast, said Major General Qassim Atta, spokesman for Baghdad operational command.
"At 11.45 am (local time), a woman wearing an explosives-filled belt blew herself up in the middle of a crowd of pilgrims going to Karbala," said Atta.
An interior ministry official said 16 people had been killed in the attack and confirmed that 38 pilgrims had been wounded.
The victims had been travelling on foot from the central province of Diyala and had stopped at a food tent set up for pilgrims heading for Karbala, a holy Shiite city 110 kilometres south of Baghdad, to observe Arbaeen rituals.
Arbaeen marks 40 days after the Ashura anniversary that commemorates the killing of revered 7th century Imam Hussein, whose shrine is considered one of the holiest places of Shiite Islam.
Tens of tens of thousands of Shiites, including many from neighbouring Iran, make their way at Arbaeen to pay homage at the Imam Hussein shrine in Karbala, walking as a sign of greater piety.