Documents found at Osama Bin Laden's Pakistan home suggest he was planning new attacks on the US, including on the 9/11 anniversary, US reports say.
One plan aimed to target a US rail route, the reports said, although no imminent threat was detected.
Officials are examining computers, DVDs and documents seized from the Abbottabad home where they believe Bin Laden hid for up to six years.
President Obama is due to meet some of the troops involved in the operation.
He will hold private meetings on Friday at Fort Campbell, Kentucky, with at least some of the Navy Seals who took part in the raid.
On Thursday, the president visited the site of the attack of 11 September 2001 in New York, laying a wreath in memory of the nearly 3,000 victims who died at Ground Zero, and speaking to relatives at the site.
He told victims' families that justice had now been done, but that America "would never forget".
Bin Laden, the al-Qaeda leader who had been top of the US most wanted list since the attacks on New York and Washington in 2001, was killed by US special forces in northern Pakistan on Monday.
His body was then buried at sea from a US aircraft carrier.
Information about the apparent plans unearthed in Pakistan was contained in a joint FBI and Homeland Security bulletin, the Associated Press said.
The bulletin, circulated to law enforcement officials, said the idea to tamper with an unspecified US railway track was found in handwritten notes taken from Bin Laden's compound.
According to the bulletin al-Qaeda operatives planned to derail a train so that it would plunge into a valley, or from a bridge, AP reported.
"While it is clear that there was some level of planning for this type of operation in February 2010, we have no recent information to indicate an active ongoing plot to target transportation and no information on possible locations or specific targets," the warning read.
One intelligence official said the notes revealed the ambition to hit the US with large-scale attacks in major cities and on key dates such as anniversaries and holidays.
'Continued to plot'
One unnamed US official told the New York Times the documents revealed that Bin Laden was not merely a figurehead for al-Qaeda sympathisers worldwide.
"He continued to plot and plan, to come up with ideas about targets, and to communicate those ideas to other senior [al-]Qaeda leaders," the newspaper quotes the official as saying.
Meanwhile, further details have emerged about Bin Laden's life in the Abbottabad compound and the exact sequence of events that lead to his death.
A senior Pakistani military official said one of Bin Laden's wives told investigators she had been living in the compound for five years, along with her husband.
New reports of the raid appear to contradict earlier information about the raid.
White House counter-terrorism adviser John Brennan had originally suggested that Bin Laden was among those who was armed within the compound.
Early accounts of Sunday night's raid had suggested a lengthy exchange of fire throughout the 40-minute operation.
But US officials now say that only one person fired on the US special forces.
He is believed to have been Bin Laden's courier, Abu Ahmed al-Kuwaiti, who was killed at the start of the raid.
Critics have raised concerns about the legality of the operation after the US revised its account to acknowledge Bin Laden was unarmed when shot dead.
However, the US has maintained that Bin Laden was a lawful military target whose killing was "an act of national self-defence".
The US raid against Osama Bin Laden was launched after months of CIA surveillance from a safe house in Abbottabad, the Washington Post reported on Friday.
Citing unnamed officials, the newspaper said the CIA's operation used satellite imagery and attempted to record voices inside the compound, but was stood down before the military operation was eventually launched.