Iran was planning attacks on four US embassies in Iraq when its top general was killed, US President Donald Trump says.
When asked what threat led to last Friday's US drone strike, he told Fox News: "I can reveal that I believe it probably would've been four embassies."
But Democrats given intelligence briefings on the fatal strike say they have seen no evidence of embassy plots.
Mr Trump first made the embassy claim at the White House on Thursday and repeated it that night at a rally in Ohio.
He was also backed up by US Secretary of State Mike Pompeo.
"We had specific information on an imminent threat and those included attacks on US embassies. Period, full stop," said Mr Pompeo as he announced new sanctions against Iran.
Soleimani, 62, was the mastermind of Iran's activities in the Middle East, as an architect of the Syrian government's war against rebels and the rise of pro-Iranian paramilitaries in Iraq.
Mr Trump and Mr Pompeo have said Soleimani was responsible for the deaths of thousands.
The killing of Gen Qasem Soleimani, a national hero, came after days of protests at the US embassy in Baghdad.
American forces also targeted Abdul Reza Shahlai on 3 January, a key Iranian commander and financier living in Yemen, US media reported on Friday.
They quote unnamed US officials as saying that the secret mission did not result in the commander's death.
Washington has so far made no public comment on the reported US raid in Yemen.
On Friday, the White House authorised new sanctions against Iran that were designed to "stop the Iranian regime's global terrorist activities", US Treasury Secretary Steve Mnuchin said.
He said the penalties would affect Iran's construction, manufacturing and mining industries. Mr Pompeo said the targets were Iran's "inner security apparatus".
In a statement, Mr Trump called Iran the "world's leading sponsor of terrorism" and vowed to counter Iranian threats "until the Iranian regime changes its behaviour".