Jordanian security services foiled the plot in April last year. Jordanian officials say that had it been carried out, thousands of people would have died.
The late leader was reportedly issued a domicile certificate.
His visit to Iraq comes less than a week after a US air strike killed Abu Musab al-Zarqawi, the leader of the al Qaeda in Iraq.
The incident occured when thousands of Shias marching across a bridge in a religious procession heard rumours that a suicide bomber was about to attack, triggering a stampede.
The al-Tawhid wal-Jihad group said in a statement posted on the internet that it had killed the second American, believed to be Jack Hensley.
There are unconfirmed rumors from multiple sources in the Middle East that the al-Qaeda frontman was killed in a raid by US forces in Mosul, it said. However, the report cannot be verified until the intelligence firm gets other evidence.
'There has been communication between bin Laden and Zarqawi within the past two months, during which bin Laden suggested to Zarqawi to involve himself in attacks in the United States,' a US counter-terrorism official said.
The Sunday Times, London, quoted eye-witnesses as saying that US troops beat him to death.
A rare look inside Osama bin Laden's Afghan hideout.
Death came calling for the 71- year-old terrorist from the sky on Sunday morning in Kabul.
The United States has offered rewards amounting to USD 20 million (around Rs 127 crore) for tips on whereabouts of four top leaders of the Islamic State, a day after the terror group claimed responsibility for its first attack on American soil.
'No other terror organisation has valued popular consensus as the Islamic State does -- instead of repressing people, IS wants to gain their support. This is a major innovation in terrorism,' says terrorism expert and author Dr Loretta Napoleoni in an interview to Archana Masih and Syed Firdaus Ashraf/Rediff.com.