Secretary of State John Kerry said today that the United States hasn't abandoned a former FBI agent believed held in Iran who recently was outed in press reports as a CIA agent.

Kerry said efforts to find Robert Levinson and two other Americans held in Iran "are being worked aggressively."

"Well, there hasn't been progress in the sense that we don't have him back. But, uh, to suggest that we have abandoned him or anybody has abandoned him is simply incorrect, uh, and -- and not helpful," he told ABC's "This Week" in an interview from Ho Chi Minh City, Vietnam, where he is on a diplomatic visit.

"The fact is, that I have personally raised the issue not only at the highest level that I have been involved with, but also through other intermediaries. So we don’t have any meeting with anybody who has something to do with Iran or an approach to Iran where we don’t talk to them about how we might be able to find not just Levinson, but we have two other Americans that we’re deeply concerned about."

Levinson's family has told reporters that they feel the U.S. government has abandoned and betrayed him. Members of Congress also have expressed concerns that Levinson's fate -- and that of Iranian-American pastor Saeed Abedini and former Marine Amir Hekmati -- is taking a back seat to the administration's desire to secure a deal limiting Iran's nuclear program.

It's hard to dispute those concerns when the whole world knows a nuclear deal with Iran is one of President Obama's two principal policy goals in the Middle East, with the other being an Israel-Palestinian peace treaty. And the Iranians have a long history of exploiting the West's desire for negotiations to their advantage by holding the very idea of talks hostage. Under those circumstances, what leverage does the administration have to secure Levinson's release, or anyone else's?