At least 12 people were killed and 26 wounded on Saturday in a car bombing near a marketplace in the Iraqi capital Baghdad, police said.
The bomb went off on a road used by Shiite pilgrims in the neighbourhood of Nahrawan in south-eastern Baghdad, local media reported.
The pilgrims were on their way to visit the holy shrine of Imam al-Khadim in northern Baghdad. But it wasn't immediately clear if pilgrims were among the casualties.
No one has claimed responsibility for the bombing.
Previous similar attacks have been claimed by the Islamic State extremist Sunni militia, which regards Shiites as heretics.
The bombing comes as Iraq is also grappling with a political crisis over reforms, and Prime Minister Haider al-Abadi is trying to form a new government of independent technocrats.
Major political blocs in parliament have blocked the move in recent weeks.
Iraqi governments have been formed along political and sectarian lines since the US-led 2003 invasion that deposed Saddam Hussein.
Critics say the system contributes to corruption.
Al-Abadi, a Shiite politician, has warned that the current crisis can hamper the country's US-backed fight against Islamic State, which controls key areas in Iraq's Sunni heartland.