GOP senator to Obama: Explain Iran payment
© Greg Nash

Sen. James Lankford is demanding President Obama hand over details on the Iran nuclear deal and a separate $1.7 billion settlement.

The Oklahoma Republican will send a letter to the president Thursday, noting that Obama "promised transparency" when he took over the White House.
"The American people rightfully have questions about how this transfer took place and deserve to know the full extent of the relationship between the U.S. and Iran," Lankford writes in the letter, which was obtained by The Hill.
Lankford's letter comes after The Wall Street Journal reported that the Obama administration transferred $1.3 billion in cash to Iran in addition to an initial payment of $400 million. 
The State Department disclosed the additional $1.3 billion payment late last month, and has linked the overall $1.7 billion settlement to a decades-old arms sale. 
Lankford, in Thursday's letter, wants Obama to explain why the payments were made in cash and if the administration can account for how Iran is spending the money, including if it's being used to back terrorism. 
He also wants to know about any "direct or indirect payments" from the U.S. to Iran since mid-2015, when the separate nuclear agreement was announced, or any ongoing negations for other settlements with Iran. 
Republicans for weeks have seized on the timing of the first payment, which coincided with the release of U.S. hostages in Iran, to question if it was a ransom. The fallout over the settlement is the latest in a string of fights between GOP lawmakers and the White House since Congress failed last year to block the nuclear agreement.
Lankford is also pressing Obama to respond to a report from the Institute for Science and International Security, a Washington-based think tank, finding that Iran was exempted from some of the nuclear agreement's restrictions. Under the deal, Iran limits its nuclear program in exchange for the lifting of some sanctions. 
Lankford wants to know what changes to the deal's guidelines were made, if any other exemptions for Iran are being considered and why the changes were "kept hidden from the American people." 
"The American people should know how their hard earned tax dollars were spent and the details of the agreements that were made on their behalf," Lankford added in the letter. "Every American's signature was implicitly placed on that agreement by your administration, so every American should have access to the facts of the agreement."