Tens of thousands of Shiite pilgrims are converging on a golden-domed Shiite shrine in Baghdad to commemorate the anniversary of the death of a revered imam.

Some of the pilgrims in the Iraqi capital's northern neighborhood of Kadhimiyah, where the 8th century Imam Moussa al-Kadhim is buried, are pounding their chests in grief while others are flagellating themselves with chains or carrying a symbolic coffin of the imam, wrapped in a green cloth.

The annual commemoration events culminate on Tuesday.

Security forces have blocked major roads in Baghdad to protect the pilgrims, who have been making their way on foot this week to the shrine.

But Sunni extremists, who see Shiite as apostates, have still managed to launch several attacks, including a car bombing Monday that killed 18 pilgrims.