A suicide bomber has blown up his vehicle at Iraq's forensics headquarters in central Baghdad, killing 18 people and injuring 80.
Five police officers and 13 civilians are among the dead.
Iraqi military spokesman in Baghdad Major General Qassim Atta said the attack targeted the forensics institute in the central neighbourhood of Karrada, which had been bombed twice before.
An interior ministry official said the blast had wrecked the institute.
The blast came a day after three huge and apparently co-ordinated minibus bombs targeted hotels in Baghdad, killing at least 36 people and wounding 71.
Iraqi politicians and US forces have warned of rising violence ahead of the 7 March vote, the second parliamentary ballot since the 2003 US-led invasion ousted Saddam Hussein and ushered in a deadly and long-lasting insurgency.
Monday's hotel bombings came on the same day the government announced that Ali Hassan al-Majid, a symbol of the fallen regime, had been executed.
Majid, better known by his nickname ‘Chemical Ali’, was hanged just days after he was sentenced to death for the 1988 gassing of thousands of Kurds, a crime that shocked the world.
The execution comes amid a bitter row sparked by the exclusion of hundreds of candidates from the election because of their alleged links with Saddam Hussein, which could see Sunni Arabs marginalised from the political process.
The election is seen as a crucial step towards consolidating Iraq's democracy and securing a complete US military exit by the end of 2011, as planned.
The dispute over the election list has alarmed the US and the latest bombings will add to Washington's concerns.
Yesterday's attacks differed from recent high-profile bombings in Baghdad in that they targeted hotels, one of the capital's few remaining symbols of tourism, rather than government buildings.
Nearly 400 people were killed and more than 1,000 were wounded last year in co-ordinated vehicle bombings at government buildings, including the ministries of finance, foreign affairs and justice in August, October and December.
Insurgents, weakened in the past year, have in the past six months changed tactics and mounted successful attacks on ‘hard’ targets such as government offices, rather than so-called soft targets in civilian areas.
There are widespread fears, in the wake of the bloody attacks to hit Baghdad in the second half of 2009, that political violence will rise in the weeks leading up to the March vote.
US Secretary of State Hillary Clinton said extremists were trying to upend progress toward democracy, while UN chief Ban Ki-moon urged Iraqis to remain on a path to reconciliation despite persistent unrest that plagues the country.
US Vice President Joe Biden made a 24-hour visit to Baghdad at the weekend after which he said he was confident Iraq's leaders would find a ‘just’ solution to the exclusions issue.
