A car bomb targeting Shia pilgrims killed at least 18 people in southern Baghdad on Monday, security and medical sources said.

The attack took place in the Baghdad area of Saydiya, according to reports. The number of wounded is unclear with different sources putting it anywhere between 28 and more than 40.

Women and children are understood to be among the victims.

The Islamic State (IS) group claimed responsibility for the attack.

Tens of thousands of Shias have been making their way to the northern Baghdad neighbourhood of Kadhimiyah to visit the place where eighth-century Imam Moussa al-Kadhim is said to be buried.

IS carried out a similar attack against pilgrims on the outskirts of Baghdad on Saturday, killing at least 23 people.

Many of the main thoroughfares in Baghdad are closed in the days leading up to the annual commemoration of Imam Musa Kadhim's death, an important date in the Shia Muslim calendar.

Kadhim, the seventh of 12 imams revered in Shia Islam, died in 799 AD.

The pilgrimage to his shrine in northern Baghdad has in recent years turned into a huge event that brings the capital to a standstill for days.

The main commemoration at the shrine in the Kadhimiyah area of Baghdad will take place on Tuesday.