The head of the national security division at the Justice Department was among the agency’s senior officials who objected to paying Iran hundreds of millions of dollars in cash at the same time that Tehran was releasing American prisoners, according to people familiar with the discussions.

John Carlin, a Senate-confirmed administration appointee, raised concerns when the State Department notified Justice officials of its plan to deliver to Iran a planeful of cash, saying it would be viewed as a ransom payment, these people said. A number of other high-ranking Justice officials voiced similar concerns as the negotiations proceeded, they said.

The U.S. paid Iran $400 million in cash on Jan. 17 as part of a larger $1.7 billion settlement of a failed 1979 arms deal between the U.S. and Iran that was announced that day. Also on that day, Iran released four detained Americans in exchange for the U.S.’s releasing from prison—or dropping charges against—Iranians charged with violating sanctions laws. U.S. officials have said the swap was agreed upon in separate talks.

The objection of senior Justice Department officials was that Iranian officials were likely to view the $400 million payment as ransom, thereby undercutting a longstanding U.S. policy that the government doesn’t pay ransom for American hostages, these people said. The policy is based on a concern that paying ransom could encourage more Americans to become targets for hostage-takers.

At a press conference last week, President Barack Obama described the controversy as the “manufacturing of outrage in a story that we disclosed in January,’’ when the U.S. settled a number of outstanding issues with Iran.

He added, “We do not pay ransom for hostages.”

A Justice Department spokesman has said the agency “fully supported the ultimate outcome of the administration’s resolution of several issues with Iran,’’ including the settlement of the long-running arms case, “as well as the return of U.S. citizens detained in Iran.’’ The department has declined to discuss interagency deliberations.

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