President Obama holds a news conference at the Pentagon on Thursday to explain the $400 million delivered to Iran.
He took the opportunity to defend the landmark nuclear accord that the U.S.-led global coalition reached with Iran more than a year ago.
Pastor Saeed Abedini, one of the four American hostages released by Iran on January 16, said that their plane was loaded and ready for departure, but clearance was withheld for hours pending the arrival of another aircraft.
The impetus for renewed questions about a publicly announced settlement was a Wall Street Journal account of the transaction, which revealed that the $400 million was "converted into other currencies, stacked onto the wooden pallets and delivered to Iran on an unmarked cargo plane", as the paper described it.
The timing of the payment raised suspicions whether it was made in exchange for the release of the jailed Americans.
So while that payment went through at the same time, US officials say it was unrelated to the Americans being freed.
According to the WSJ's report on Wednesday, the DOJ's objection - that the money would be seen as a ransom payment - was overruled by the State Department.
"The Obama-Clinton foreign policy gave rise to ISIL, made Iran flush with cash, and is now admitting vast numbers of refugees and migrants into the United States from some of the most volatile regions in the world", Trump senior policy adviser Stephen Miller said in a statement.
Obama says the group may continue to inspire people to carry out lone wolf-type attacks on subways or parades to sow fear and elevate its profile.
At the time, the United States said it had settled a long-standing Iranian claim at the Iran-U.S. Claims Tribunal in The Hague, releasing $400 million in funds frozen since 1981, plus $1.3 billion in interest that was owed to Iran.
And questioning if he can trust Vladimir Putin to help stem the violence - acknowledging the failing Syrian cease-fire agreement between Russian Federation and the U.S.
The transfer of cash, Obama said, was necessary because the administration was heeding the strict banking sanctions that negated the possibility of using a wire transfer.
"There was no benefit to the United States of America to drag this out", he said.
In this case, the prisoners and the cash were loose ends to the larger agreement that blocks Iran from developing nuclear weapons for at least a decade, in return for relief from worldwide economic sanctions.
Vigorously disputing President Obama's claim that Israeli officials now support the Iran nuclear deal, Israel's Defense Ministry compared last year's deal to the Munich Agreement of 1938. In response to the release of the Americans, the US released seven Iranian citizens and dropped extradition requests for 14 others at the time.