At least 47 recruits and soldiers were killed and 77 wounded when a suicide bomber blew himself up at an army recruitment centre in Baghdad on Tuesday, two weeks before the end of the US combat mission in Iraq.
The blast which tore through a line of recruits was one of the bloodiest this year. Tensions are simmering following an inconclusive election more than five months ago that has yet to produce a new government.
Insurgents have been targeting Iraqi police and soldiers as they prepare to take full responsibility for security on September 1, when the United States ends its seven-year combat mission.
US troop numbers will be reduced to 50,000 for a training mission before a full withdrawal planned for next year.
"We were lined in a long queue. There were also officers and soldiers. Suddenly an explosion happened. Thank God only my hand was injured," recruit Saleh Aziz told Reuters Television while doctors in al-Karkh hospital treated his wounds.
The toll of 47 in the attack on an army base near Baghdad's central Maidan square was final and not expected to increase, deputy health minister Khamis al-Saad told Reuters. Some police and army sources said the death toll could be as high as 52, with more than 120 wounded.
The site of the attack used to be the defence ministry under Saddam Hussein, turned into an army recruitment centre and military base after the 2003 US-led invasion.
One army source who declined to be identified said there might have been two suicide bombers, a hallmark of Sunni Islamist al-Qaeda and its local affiliates.
"They (the recruits) were gathering in large numbers. They let in 250 recruits at a time," the source said.
A source at a Baghdad morgue said it had received remains of the male bomber.
The bloodshed was the latest in a steady drumbeat of attacks since a March 7 election produced no outright winner and pitted a Sunni-backed, cross-sectarian alliance against the country's major Shi'ite-led factions.
While overall violence in Iraq has fallen sharply since the height in 2006-07 of the sectarian slaughter between majority Shi'ites and once dominant Sunnis, a stubborn insurgency remains capable of carrying out large scale attacks.
On August 7 around 45 people were killed when two or three explosions struck a market in the southern oil hub of Basra, and at least 39 people were killed on July 18 when a suicide bomber attacked government-backed Sunni militia as they lined up to be paid on Baghdad's southwestern outskirts.
On May 10, around 125 people were killed nationwide in a wave of assaults by al-Qaeda-linked militants who security officials said were trying to prove they remained a potent force despite the deaths of many of their leaders earlier this year.
Officials say the insurgents are now trying to exploit political tensions stirred up by unsuccessful coalition talks between Shi'ite political factions and the Sunni-backed Iraqiya alliance, which won a narrow victory in the March election.
Hopes of a one possible solution to the stalemate were dashed on Monday when Iraqiya, headed by former premier Iyad Allawi, broke off talks with prime minister Nuri al-Maliki.
They also want to undermine faith in the Iraqi security forces as US troops and war materiel depart.
