According to the public radio report, Panetta arrived in Israel two weeks ago for a round of talks with Prime Minister Benjamin Netanyahu, Defence Minister Ehud Barak and other top officials.
The talks focused on Iran's nuclear programme, which the United States and Israel suspect is aimed at developing an atomic bomb, a claim denied by Tehran.
The Israeli leaders assured Panetta that "Israel does not intend to surprise the US on Iran."
President Barack Obama's decision to engage Tehran in direct talks in an effort to end the nuclear standoff have raised concern in Israel which called on the negotiations to be limited in time and accompanied by tough sanctions.
Israel nevertheless refuses to remove the option of taking military action against the Islamic republic.
Netanyahu has said that Iran's nuclear ambitions posed an "existential threat" to the Jewish state.
