President Donald Trump on Thursday seized upon an investigation by Senate Republicans that found the Obama administration secretly tried to give Iran brief access to the U.S. financial system after the 2015 Iran nuclear deal. This would have sidestepped U.S. sanctions still in place.

Trump wrote on Twitter, that the efforts were “totally illegal” and called for an investigation.

The Obama Administration is now accused of trying to give Iran secret access to the financial system of the United States. This is totally illegal. Perhaps we could get the 13 Angry Democrats to divert some of their energy to this “matter” (as Comey would call it). Investigate!

— Donald J. Trump (@realDonaldTrump) June 7, 2018

The plan failed when two U.S. banks refused to participate, but the Treasury Department’s issuing of a license to allow Iran to convert $5.7 billion it held at a bank in Oman was not illegal.

Senate Republicans contend the Obama administration misled the American people because it had repeatedly promised Congress that Iran wouldn’t gain access to America’s financial system. Trump withdrew from the landmark Iran nuclear deal last month.

Former Obama administration officials have said the decision to grant the license adhered to the spirit of the agreement, which included allowing Iran to regain access to foreign reserves that had been off-limits because of U.S. sanctions.

They also dispute whether providing the momentary access to U.S. banks to convert funds through the dollar constituted “access to the U.S. financial system.”

Opponents of the Iran nuclear deal have said the U.S. was too lenient with Iran and the windfall would have been used to fund extremism and other destabilizing activities.

The Treasury Department license, issued in February 2016 and never previously disclosed, would have allowed Iran to convert $5.7 billion it held at Oman’s Bank of Muscat from Omani rials into euros by exchanging them first into dollars.

If the Omani bank had allowed the exchange without such a license, it would have violated sanctions that bar Iran from transactions that touch the U.S. financial system.

(AP)