"Severed hands and legs were falling over me," the Associated Press news agency quoted Ali as saying.
"I was soaked with blood from the body parts and wounded and dead people falling over and beside me."
Target of attacks
Al Jazeera's Omar Al Saleh, reporting from Baghdad, said the centre was busy on Tuesday because the defence ministry had recently called on new recruits to join the army.
"According to a police source they were standing in the hundreds," he said.
"Violence has escalated since the elections. Any longer delay would leave Iraq on the verge of civil war"
Saad al-Muttalibi, official at Iraqi ministry of dialogue and reconciliation
"Then a suicide bomber wearing an explosive belt [and] wearing an army uniform was talking to those recruits, pretending that he was trying to get their names, so people gathered around him and he detonated his charge.
"This is the deadliest attack since the start of [the Muslim holy month of] Ramadan, and the deadliest perhaps in the last month or so."
Security forces have been frequent targets of attack since the start of army restructure after the US-led invasion.
Tuesday's attack comes two weeks ahead of a US deadline to cut its troop numbers to about 50,000 and a day after Iraqi lawmakers suspended talks on forming a new government.
The Iraqiya bloc headed by Iyad Allawi, Iraq's former prime minister, said on Monday that it had suspended talks with the State of Law bloc headed by Nouri al-Maliki, the country's incumbent prime minister, in protest against al-Maliki's "sectarian tone".
Our correspondent said different armed groups appear to be trying to take advantage of the power vacuum in Iraq, as lawmakers squabble over positions in a new government more than five months after an inconclusive March 7 election.
"Everyone you speak to here is concerned that attacks could get more frequent because of the US withdrawal plans and months of political uncertainty in Iraq," he said.
|Violence has been on the rise in Iraq in recent months, hitting a two year high in July
Saad al-Muttalibi, a member of al-Maliki's bloc and a senior official at the ministry of dialogue and reconciliation told Al Jazeera that the political situation plays a role in the deteriorating security in Iraq.
"Definitely there is a political background to this. Violence has escalated since the elections," he said.
"Any longer delay would leave Iraq on the verge of civil war. No political party would gain from that."
But Wafiq al-Samarai, a former Iraqi intelligence chief and security adviser to Jalal Talabani, Iraq's president, said it is the lawmakers themselves who are responsible for the security failure.
"Politicians are responsible for what is happening, because they excluded Iraq's veteran and experienced intelligence officers for sectarian and revengeful motives. Moreover, they are oppressing the current ones by passing their reports to militias of ruling parties.
"As a result, intelligence officers are scared to do their jobs and this is the result, attacks everywhere," he told Al Jazeera.