Senior U.S. Department of Justice (DOJ) officials objected to sending $400 million in cash to Iran at the same time as the country released American prisoners, the Wall Street Journal has revealed.

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.

To read the full WSJ report, click here.

The WSJ reported on Tuesday that the cash was the first installment of a $1.7 billion settlement the U.S. Government had reached with Iran to solve a 1979 arms deal dispute.

The cash was packed in pallets and airlifted to Tehran by cargo plane, and was portrayed in the Iranian press as a random payment for five Americans, the WSJ reported.

The American prisoners were released on January 16, at the same time as the U.S. released seven Iranians - a prisoner swap that coincided with the lifting of international sanctions. At the time, the U.S, said that it had released $400 million in funds as part of a settlement of the arms deal dispute, but did not specify that cash had been airlifted to Tehran.

White House spokesman Josh Earnest said on Wednesday that the payment was neither a ransom, nor paid in secret.

Follow CNBC International on Twitter and Facebook.