Jim Muir says recent attacks come against a backdrop of improved security
A suicide car bomber has killed at least 18 people and injured 80 at a government forensics centre in the Iraqi capital Baghdad, police say.
The attacker apparently tried to drive through a police checkpoint and blast walls protecting the centre in the Kerrada district.
The building was badly damaged by the massive blast, and the rubble is being searched by rescue teams.
On Monday, bomb attacks near well-known hotels in the city killed 36 people.
This is the latest in a series of attacks on official buildings, including those to do with crime and punishment.
The justice ministry was badly damaged in October by a huge truck bomb, and a court complex was hit in December.
There have been fears that attacks will increase as the parliamentary election approaches in March and those predictions seem to be coming true, the BBC's Jim Muir reports from Baghdad.
'Vehicles in flames'
An Iraqi military spokesman, Maj Gen Qassim Atta, said the suicide bomber had raced his vehicle towards the Criminal Evidence Department on al-Tahariyat Square at 1045 (0745 GMT).
One of Monday's victims was a former national basketball team player
Most of the casualties were staff from the forensics centre, he said, adding that it had been targeted by two bomb attacks in the past.
Hassan al-Saidi, a mechanic who works in the area, said he had seen at least five vehicles in flames and more than a dozen people wounded by flying glass.
"I've heard many explosions in the past but nothing like this," he told Reuters news agency.
The Associated Press news agency reported that rescue teams in blue jumpsuits were combing through the debris of the three-storey building as a crane removed some of the fallen blast walls.
Funerals have been taking place on Tuesday for victims of Monday's attacks.
Grieving relatives held a funeral procession through Baghdad for Monthir Ali Shnawa, a former Iraqi national basketball team player.
In another development, the body of executed Saddam aide Ali Hassan al-Majid is due to be collected by a family member on Tuesday, AP reports.
A grave has been dug for "Chemical Ali", who was hanged on Monday, in his home town of Tikrit, the agency adds.