The Islamic State militant group claimed a bombing on Monday in the Iraqi capital which it said killed 40 Shia pilgrims, US terrorism-tracking website SITE reports.
In an online statement, IS's Baghdad Province branch took credit for the alleged suicide bombing in Baghdad's al-Dora district in the capital, SITE said.
Iraqi officials denied the attack was a suicide blast and said it had killed at least 18 Shiite pilgrims who were commemorating the anniversary of the death of a revered imam.
At least 18 people were wounded in a car bombing, police said.
Security forces have blocked major roads in Baghdad in anticipation of attacks against pilgrims making their way from all over Iraq to Baghad's Kadhimiyah district, where the 8th century Imam Moussa al-Kadhim is buried.
IS also claimed twin car bombings in the southern Iraqi city of Samawah on Sunday which officials said killed at least 31 people and wounded 52.
