At least 13 people have been killed in a car bomb targeting one of Iraq's top Shia political leaders.
Injured were ferried to several hospitals in Baghdad
Thirty-nine people were wounded in the attack outside offices of the Supreme Council for the Islamic Revolution in Iraq (Sciri) in Baghdad.
Sciri leader Abdel Aziz al-Hakim was not injured in the blast and has urged supporters not to take revenge.
Violence has been escalating ahead of elections set for 30 January, in which Sciri is likely to play a major role.
Last week a double suicide attack in the Shia cities of Najaf and Karbala killed about 70 people.
Leaders of the majority Shia population said the bombings were an attempt to provoke sectarian conflict in Iraq.
In a separate development, the leader of Iraq's largest Sunni Muslim party said it was withdrawing from elections, having demanded a six-month postponement to ensure broader participation in the vote.
The Sciri leader blamed Monday's morning rush-hour attack on a Sunni insurgent alliance of former Saddam loyalists and Islamists.
The car bomb exploded at the gate of the building, where Mr Hakim has his home and offices, destroying about 30 cars near the entrance.
The house previously belonged to former deputy Prime MinisterTariq Aziz, a senior ally of Saddam Hussein who has been detained since April 2003.
Reports say that at least three people from an allied party - the Iraqi Hezbollah party - were killed in the attack.
"We have chosen the path of non-violence and we will stick to it," Mr al-Hakim told Reuters news agency from the compound.
"The only ideology these people know is terror," he added. "We laid down our arms in favour of pluralism. If we wanted violence we would have responded a long time ago."
Sciri, a religious party formed by exiled Iraqi Shias in Iran during Saddam Hussein's rule, has a powerful armed wing, the Badr Brigade.
The founder of Sciri and brother of the current leader, Ayatollah Muhammad Baqr al-Hakim, was among about 100 people killed in a massive car bombing in Najaf in August 2003.