Secretary of State John F. Kerry waves as he is discharged from Massachusetts General Hospital on Friday. (AP)

Secretary of State John F. Kerry on Tuesday said the United States is more concerned about preventing Iran from developing nuclear weapons than it is with getting Tehran to publicly acknowledge past work to develop a bomb.

“We’re not fixated on Iran specifically accounting for what they did at one point in time or another. We know what they did,” he said in a video call with reporters at the State Department. Kerry spoke from his Boston home, where he has been recovering after breaking his leg in a bicycling accident in Europe.

“It’s critical to us to know that, going forward, those activities have been stopped and that we can account for that in a legitimate way,” he said. “That clearly is one of the requirements, in our judgment, for what has to be achieved in order to have a legitimate agreement.”

Kerry’s remarks suggest a possible compromise the United States is willing to make to strike a deal. Negotiators are facing a June 30 deadline to reach an agreement that would rein in Iran’s ­nuclear program in exchange for lifting sanctions. But any compromise is likely to stiffen opposition in Congress from members who want Iran to admit it conducted weaponization research more than a decade ago.

Iran has so far not cooperated with efforts by the International Atomic Energy Agency to document suspected military aspects of its nuclear research in a program that many experts believe was abandoned in 2003.

An acknowledgment of that work would highlight the contradiction inherent in a 2003 fatwa issued by Iran’s supreme leader, Ayatollah Ali Khamenei, that, according to some interpretations, banned the production and use of nuclear weapons as a sin under Islam.

The American Israel Public Affairs Committee has lobbied against an Iran deal if it lacks an explanation of the “possible military dimensions” of Tehran’s nuclear research. AIPAC argues that an admission is needed because allowing Iran to sidestep a full accounting, as required under U.N. Security Council resolutions, would encourage the country to ignore its commitments in any new deal.

Some members of Congress have criticized the Obama administration as appearing to make too many compromises in its eagerness to secure a deal.

The administration has said it is willing to walk away from the table if it does not get a “good” deal. Kerry said Tuesday there can be no sanctions relief without guarantees that Iran will not build nuclear weapons in the future.

Kerry’s appearance Tuesday, shortly before he was due to fly back to Washington, underscores his readiness to return to a full schedule after more than two weeks of being sidelined by his bicycling injury. He said he would soon leave for Europe to lead the Iran negotiations underway in Vienna.

Kerry’s presence at the talks, in which five other world powers are partners with the United States, is considered crucial to their success.